Perhaps the most popular metric used in evaluating the performance of aquarium pumps has been rate of flow, usually expressed in gallons or liters per hour (g.p.h., or l.p.h., respectively). However, there is more (or correctly, less) to the story. Although oceanographers and limnologists may on occasion be interested in flow rates, the metric most often reported is simply velocity (inches per second, centimeters per second, etc.).

As aquarists, we know the rate of flow from aquarium pumps depends upon many factors, including the size of the pump's discharge area (or diameter, since most pump discharges are round). Since the equation for calculating a Flow Rate (g.p.h. /l.ph.) = Area (of the pump discharge) * Velocity (or Q = V*A), increasing or decreasing the discharge area affects the velocity of the water flow exiting the pump. Hence, velocity is the most critical parameter. This is important - velocity that is too high can cause harm to sessile invertebrates' tissues. On the other hand, low velocity fails to deliver the desired effects of having a pump in the first place. This article will look at water motion based simply on velocity as tested within a relatively large home aquarium and briefly examine water velocities seen in real reefs and lagoons. Together this information will allow hobbyists to make informed decisions on pump selection and pump & invertebrate placement.

Pumps Tested

All pumps tested for this article are manufactured by Tunze Aquarientechnik GmbH (Penzburg, Germany) and are of the 'nanostream' series, including models 6015, 6025, 6045 (with a mechanical discharge adjustment), 6055, and 6095. These pumps use small electric motors connected to a propeller to move water.

Water Velocity Categories

Water velocity has long been recognized as an important factor on natural coral reefs and there is much valuable information available to hobbyists. The categories chosen for this article were developed by one of the more prolific researchers of coral reef water flow dynamics - Kenneth Sebens. In his 1997 work, Seben's categorized water velocities into 4 zones.

• Low: Velocity of <1 to 5 centimeters per second (<~1/2" to 2" per second). This zone is periodically found on deeper (>25m, or ~82 feet depth) fore-reefs, isolated tide pools (such as at low tide), lagoons, and back-reefs.
• Moderate: Velocity of 6 to 20 centimeters per second (~2" to 8" per second). Mid- to shallow-fore reefs often experience these flows.
• High: Water speed of 21 to 50 centimeters per second (~8" to 20" inches per second). High velocities found in surf zones.
• Very High: Velocity exceeds 50 centimeters per second (>20" per second). Also found in some surf zones, storm surges, reef spur and grooves, etc.
• Note that these categories are not all inclusive - oceanic water velocity can sometimes be measured in meters per second.

See Figure 1.

Testing Protocol

Pumps were testing in a 240-gallon aquarium (24"x24"x96") filled with saltwater at a specific gravity of 1.025. Water velocities were measured by a FloMate 2000 electronic water velocity meter (Marsh-McBirney, Maryland, USA). The meter's probe was held in place by a jig to measure water velocity on a horizontal plane at depth equal to that of the center of the pump's discharge. The jig was designed to also measure velocities on the x- and y- axes. Measurements were taken at approximately 2 inch increments on the x- and y-axes (the z-axis being fixed at one depth). These measurements were logged into MS Excel, with a surface area chart selected, and printed. Outlines of the rough flow patterns were traced, scanned, and exported to MS Paint where the different velocity zones were colored. These drawings were further enhanced in MS PowerPoint.

Velocity attenuation (weakening) charts were made using velocity data collected at distances from the highest velocity recorded (generally at the center of the pump discharge). Bear in mind that these measurements were made in a bare aquarium where no aquascaping offered obstruction to flow.

Tunze Pump Flow Discharge Characteristic

An important first step in the visualization of a pump's discharge is its basic shape in an unrestricted environment. In all cases reported here (except for the model 6045, when the throttle is positioned neat the pump's motor), Tunze pumps produce jet-like streams (as opposed to a diffusive fan-like pattern). See Figure 2.

With the preliminaries out of the way, we will begin our examination of Tunze nanostream pumps, starting with:

Pump: 6015 nanostream

• Maximum Discharge Velocity: 1.49 feet/sec
• Manufacturer Recommends for Tanks: 11 to 53 gallons
• Volts: 120.8
• Amps: 0.05
• Watts: 4.1
• Hertz: 60

See Figures 3 and 4.

Pump: 6025 nanostream

• Maximum Discharge Velocity: 1.69 feet/sec
• Manufacturer Recommends for Tanks: 11 to 53 gallons
• Volts: 120.4
• Amps: 0.10
• Watts: 8.0
• Hertz: 60

See Figures 5 and 6.

6045 nanostream

This pump is of a different design than the other nanostreams in that it has a sliding collar within the discharge nozzle that be moved to regulate flow. Interesting, this device has an impact on flow velocity and flow pattern.

Pump: 6045 nanostream , adjustable throttle towards motor

• Maximum Discharge Velocity: 1.31 feet/sec
• Manufacturer Recommends for Tanks: 11 to 132 gallons
• Volts: 121.6
• Amps: 0.12
• Watts: 10.4
• Hertz: 60

See Figure 7.

Pump: 6045 nanostream , adjustable throttle towards discharge Maximum Discharge Velocity: 2.44 feet/sec Manufacturer Recommends for Tanks: 11 to 132 gallons Volts: 121.3 Amps: 0.10 Watts: 7.8 Hertz: 59.9

See Figures 8 and 9.

Pump: 6055 nanostream

• Maximum Discharge Velocity: 2.67 feet/sec
• Manufacturer Recommends for Tanks: 11 to 264 gallons
• Volts: 120.5
• Amps: 0.21
• Watts: 13
• Hertz: 59.9

See Figures 10 and 11.

Pump: 6095 nanostream

• Maximum Discharge Velocity: 3.36 feet/sec
• Manufacturer Recommends for Tanks: 26 to 264 gallons
• Volts: 120.7
• Amps: 0.30
• Watts: 17.6
• Hertz: 59.9

See Figure 12 and 13.

Comments

The nanostream series offers a variety of options for hobbyists. Interestingly, the pump motor's wattage does not necessarily indicate the degree of performance.

An aquarist must first determine the requirements of the captive invertebrates. This could include close observations of other aquaria and reading aquaria (or scientific) literature. An in-depth analysis of requirements is well beyond the scope of this article but general guidelines can be offered. Non-photosynthetic corals (such as the stony coral Tubastrea and soft corals of the genus Dendronepththya) will probably require very good water movement in order to facilitate feeding. Coral tentacles would show some movement - larger polyps should move as wheat in a field while smaller polyps should 'ripple' in the flow. This may require some work to find the 'sweet spot' - if water flow is too low, the coral will eventually not extend its tentacles at all (some researchers believe the energy required to keep polyps extended for food capture in low flow is greater than the energy required to keep polyps contracted, and the coral responds with energy conserving measures). On the other hand, flow that is too great may cause the coral to protect itself through polyp retraction. Bear in mind that some corals do not extend tentacles at all hours and some specialize in day (or night) feeding. Some researchers have described required water motion based on the structure and interstitial spaces of stony corals' skeletons (called the porosity index). This means a stony coral with widely spaced branches will require less water flow than a coral that has multiple, tightly packed branches. Keep in mind that water motion requirements will change as corals grow (especially some of the SPS corals such as Acropora species). And while on the subject of Acropora specimens, I have wondered if reports of branch tips losing tissue could be due to them growing into areas of strong water flow. With that said, using the information above, we can make further general recommendations.

Definition of Aquarium Sizes

Manufacturers often recommend minimum/maximum tank sizes for their pumps based on gallon capacity. Tunze owns an electronic flow meter and bases their recommendations on actual data; however, the type of tank (fish-only, reef, etc.) is not specified. When discussing tank sizes in this article, the following dimensions will be assumed for tanks of the following capacities:

• 10 gallon = 20"L x10"W x12"D
• 15 gallon = 24"x12"x12"
• 29 gallon = 30"x12"x18"
• 55 gallon = 48"x12"x21"
• 140 gallon = 72"x24"x19"
• 180 gallon = 72"x24"x24"
• 265 gallons = 96"x26"x24"
• 10 gallon hexagonal = 14"x13"x18"
• 20 gallon hexagonal = 19"x16"x21"
• 60 hexagonal = 27"x24"x29"

It will be assumed that a fish-only aquarium will require the least amount of flow/velocity while a full-blown reef aquarium stocked with numerous stony corals will require the most (although the same could be said for a tank containing non-photosynthetic corals require strong water motion is required to facilitate food delivery). However, resist the temptation to utilize the largest pump available - this can result in some really odd flow patterns in an aquarium. More is not always better.

It appears that the water velocities produced by these pumps is more than adequate for the smallest aquaria applications recommended by Tunze (that is, 11 gallon size for the 6015, 6025, 6045, 6055, and 26 gallons for the 6095). For the largest aquaria recommendations (53 gallon size for the 6015 & 6025; 132 gallons for the 6045, and 264 gallons for the 6055 and 6095), the velocities seen at the most distal point possible from the discharge of the pump will be in Seben's low range of 2" or less per second). This might be fine for fish-only tanks or reef tanks where careful selection of invertebrates tolerant of low water velocity has been deliberate. More than one nanostream pump will be necessary to provide adequate circulation in larger tanks. Use of the information provided on each nanostream pump (above) should help in your decision-making process.

This information is reflective of Tunze equipment available in January, 2012.

Questions? Comments? Leave them in the Comment section below, or, for a quicker response, email me at RiddleLabs@aol.com.

References

1. Sebens K.P. and T.J. Done, 1993. Water flow, growth form and distribution of scleractinian corals: Davies Reef (GBR), Australia. Proc. 7th Int. Coral Reef Symp., Guam. 1: 557-568.
2. Sebens, K.P., 1997. Adaptive responses to water flow: morphology, energetics and distribution of coral reefs. Proc. 8^th Int. Coral Reef Symp., Panama. II: 1053-1058.
3. Sebens, K., J. Witting and B. Helmuth, 1997. Effects of water flow and branch spacing on particle capture by the reef coral Madracis mirabilis (Duchassaing and Michelotti). J. Exp. Mar. Biol. Ecol., 211(1):1-28 (Abstract).

 

Build My LED is a newcomer to the aquarium lighting market. This company, based in Austin, Texas, is unique in that they offer the consumer the option of custom-configuring their lighting system. With 18 different LEDs to choose from, this allows a choice of 565,000,000 light combinations according to the website. Their lighting fixtures can also be used for horticulture, commercial and light therapy applications, in addition to aquarium lighting.

These options are currently available, and their tutorial will walk you through making your choices.

Lighting fixtures (luminaires) are available in lengths of:

• 12" (30cm)
• 24" (60cm)
• 36" (90cm)
• 48" (120cm)

Lens options allow the hobbyist to choose beam angles of:

• 30
• 45
• 60
• 75
• 90

LEDs

Build My LED uses LEDs from Luxeon Rebel and Rebel ES Philips Lighting along with those made by Everlight Shuen Electronics. While Philips is a household name, the latter company may need an introduction - Everlight is based in Taipei, Taiwan and has had an international presence since 1983. Everlight is one of the 10 largest LED companies in the world. 'Shuen' is Chinese for 'shiny' or 'bright'.

A multitude of LED spectrum options are available enabling the user to select almost any conceivable color. These include:

• Warm White (2,700K, 3,000K, 3,500K)
• Neutral White (4,000K, 4,500K)
• Cool White (5,000K, 5,700K, 6,500K)
• Ultraviolet (405nm)
• Royal Blue (450nm)
• Blue (470nm)
• Cyan (505nm)
• Green (525nm)
• Amber (590nm)
• Orange (615nm)
• Red (625nm)
• Deep Red (660nm)
• Far Red (730nm)

Fifteen LEDs are installed per foot (30cm) of fixture length.

Luminaire Dimensions

The fixture tested in this review has the following dimensions:

• 1.25" tall (32mm)
• 1.97" wide (50mm)
• 48.03" long (~122 cm)
• Cord length (luminaire to transformer) = 104" (~2.6m)
• Transformer to plug = 28" (71cm)

Optical Design

While Build My LED offers five beam angles to handle various lighting applications, I selected the 60 degree beam angle for my fixture.

Reason for Choosing Particular Colored LEDs

I get many emails asking a simple question: What is the best light? Unfortunately, there is no simple answer. If we discount the highly subjective personal preferences of light quality, the answer involves doing some homework on which types of photosynthetic organisms are maintained. For instance, the light quality required for terrestrial plants differs slightly from that needed by, say, zooxanthellae. The question of showcasing the variable fluorescence found in many corals is often a consideration. I offer the following in order to briefly touch on the subject.

Ultraviolet (Max. Wavelength ~405nm): Although Photosynthetically Active Radiation (PAR) is defined as those wavelengths 400 nanometers and above, chlorophyll a absorbs wavelengths to at least 350nm (Jeffrey et al., 1997). These wavelengths will also excite fluorescence in many of the coral fluorescence proteins.

Effect of Lens on UV Transmission

Acrylic materials often attenuate (weaken by absorption) ultraviolet wavelengths. This is not the case with the material used by Build My LED - no cutoff point is apparent at wavelengths below 380nm. Most of the radiation generated by the UV LED is in the visible range. See Figure 1.

Royal Blue/Blue (Max. Wavelength ~450/470nm): Chlorophylls found in zooxanthellae (chlorophylls a and c²) absorb blue wavelengths. Chlorophyll a (also found in terrestrial and freshwater plants) absorbs blue light at ~430nm while chlorophyll c² absorbs maximally at 450nm. These numbers shift by a few nanometers according to the solvent used to dissolve chlorophylls for testing. The accessory pigment peridinin absorbs light at a maximum of ~460nm. Chlorophyll b (found in terrestrial and aquatic plants) absorbs blue light at ~457nm. See Figure 2.

Cyan/Green (Max. Wavelength ~505/525nm): Peridinin (an accessory pigment found in zooxanthellae and associated with chlorophyll a) absorbs light at a maximum of 456nm and up to ~485nm (green-blue). This wavelength falls between the maximum produced by blue and green (or white LEDs). Cyan or green LEDs would be a good choice for those wishing to mimic a turbid coral reef environment. See comments on limits of light production by green LEDs below.

Red (Max. Wavelength ~625nm): Chlorophyll a absorbs red wavelengths at a maximum of ~662nm with a small shoulder at ~617nm. Chlorophyll c² has a small absorption peak at ~630nm.

Deep Red (Max. Wavelength ~660nm): Chlorophyll a absorbs light at a maximum of ~662nm. For terrestrial and freshwater plant enthusiasts, chlorophyll b absorbs red light at a maximum of ~646nm.

Far Red (Max. Wavelength ~730nm): Under conditions of saturating or super-saturating light intensities, far red light (absorbed mostly by photopigments associated with Photosystem I) will prevent a 'traffic jam' of electrons within Photosystem II. The use of this light by zooxanthellae is speculative on my part, but remains an interesting possibility.

White (Broad Spectrum,400-700nm): LEDs emitting 'white' light are actually blue LEDs coated with a phosphor that absorb blue light and fluoresce it in a broad bandwidth. 'White' LEDs are quite popular in luminaires built for aquaria. I chose these to offset the blueness of the light and to add small amounts of light in the yellow to red portion of the spectrum. Interestingly, the first luminaire I ordered contained green LEDs to excite the zooxanthellae accessory photopigment peridinin. After a discussion with Build My LED co-owner Nick Klase, I was advised to add neutral white LEDs to the blue ones, as these would be a more efficient source of green light (and the spectrum of this fixture is subjectively very pleasing). In the LED industry, the low quantum efficiency of green LEDs is known as the 'Green Gap'. Blue and Red LEDs are very efficient, but scientists have yet to produce green LEDs that exhibit similar radiometric efficiencies. As a footnote, I tested the cool white LEDs and found them to be 7,123K with a CRI of 87.

Light Intensity of a Custom LED Fixture

Although the two are closely linked, calculating light intensity required for corals or other photosynthetic organisms is much a much less complicated subject than spectral quality. I have written on this subject and reported data obtained by Pulse Amplitude Modulation (PAM) fluorometry. Generally, most corals will do quite well when maintained light fields of intensities ranging from 100 to 500 µmol·m²·sec (~5,000 to 25,000 lux). Tridacna clams (with their thick mantles and self-shading of zooxanthellae) are generally tolerant of more light.

Figure 3 demonstrates the light intensity of a 48" custom luminaire from Build My LED containing LEDs generating light at 450nm, 470nm and 4500K neutral white.

The 60 degree beam angle on my fixture was able to produce PAR values in excess of 550 µmol·m²·sec, which is a very high number considering the fixture only consumes approximately 75 electrical watts. If you need even more PAR, the intensity maps on the company's website claim the 30 degree beam angle can deliver over 1,300 µmol·m²·sec at the same mounting height across the length of the fixture.

In addition to high light levels, Build My LED has been able to solve two of the issues prevalent with LED fixtures in the aquarium industry. Looking at Figure 3, you will not see any lateral hotspots in the intensity map. Build My LED fixtures produce very uniform light across the entire aquarium, which is in contrast to the hotspots associated with the LED 'cluster' design currently utilized by many fixture manufacturers. The cluster design is used to avoid color separation in the aquarium (which is often referred to as the disco effect), but Build My LED utilizes a proprietary optical system design that eliminates the disco effect in the aquarium.

See Figures 4 and 5 for information on light intensities at various depths in an aquarium.

Dimming

If you want to adjust your light levels, Build My LED fixtures are dimmable with 0-10V controllers. The company offers a manual dimmer for $39.99, and the fixtures can also be dimmed with many of the control systems in the aquarium market.

Effect of Temperature on Light Production

Heat is an enemy of LEDs. Light output decreases with increasing temperature (the same can be said for fluorescent lamps), so care must be taken in order to maintain a proper temperature range. Build My LEDs has taken an approach that does not utilize cooling fans but instead relies upon dissipation of heat through a heat sink. This sink, an array of cooling fins, does a good job of getting heat away from the luminaire.

I was interested in examining how well this heat sink worked and conducted a simple experiment. The luminaire was plugged in and its temperature was monitored with an infrared non-contact thermometer every five minutes. A small fan was aimed at the fixture when temperature had reached its maximum (96F in an air-conditioned room).

See Figures 6 and 7.

I also checked the temperature of the driver during this procedure and found it to be about the same as the luminaire.

Construction

The luminaire is constructed of aluminum with plastic end caps. Ingress Protection Code (sometimes called the International Protection Code) is a system to describe an electrical component housing's ability to exclude dust and moisture. It consists of two digits - the first is for dust (scale of 0 - 6), and the second is for moisture (scale of 0 - 8). The rating for the luminaire itself is IP66, meaning the enclosure is dust tight and allows no ingress. In addition, the moisture resistance rating of '6' means the enclosure allows no ingress of water when water is sprayed from a water jet of 12.5mm (or ½") diameter from any direction at a pressure of 100 kPa (14.5 psi) and a flow rate of 100 liters (26 gallons) per minute at a distance of 3 meters (10 feet) for at least 3 minutes without harmful effect. IP66 is equivalent, in respect to dust and water ingress, to a NEMA (National Electrical Manufacturers' Association) 4 or 4X enclosure. A rating of IP66 does not mean protection against immersion or mean 'waterproof'. The driver/ ballast carries a rating of IP67, meaning it can be immersed in water of up to 1 meter (~3 feet) deep for a short period of time without harmful effects.

I don't mean to suggest that reasonable care shouldn't be exercised in order to avoid water ingress into any electrical device, but it is nice to know that these fixture and driver are built to tight standards.

Discussion

It is often advertised that LEDs have a useful life of 50,000 hours and it would be easy for a hobbyist to expect a light fixture to last something on the order of 10 years. Unfortunately, this has not been the case with many LED fixtures. Too often, cooling fans fail or the power supply dies. In a day where many LED fixtures are being offered with more and more frills, Build My LED offers no-nonsense lighting at reasonable prices. The design and engineering allows the fixture to remainrelatively cool. The electronic driver is waterproof (meaning no switches). No display of time or built-in timer is incorporated. While some may see these as disadvantages, I personally see them as strengths. It has long been my contention that the more complicated device is, the more likely it is to break. My luminaire boneyard contains more than few LED luminaires which finally failed when a cooling fan broke (often blowing humid, salt-laden air across sensitive internal electronics), or when a driver died (sometimes permanently wired into the fixture). I would much rather supply my own separate fan to cool a luminaire (if needed) than to have to disassemble a fixture and wire in a new computer-type fan, and use an inexpensive aftermarket timer. The driver with these units has a heavy-duty connector which allows driver replacement if necessary.

The anodized aluminum finish is attractive and more resistant to the effects of salt spray than some of the luminaires in painted iron boxes. In short, I want a reliable lighting device and Build My LED seems to have hit the right note.

Tips for Taking PAR Measurements

Many hobbyists use an Apogee quantum meter for taking PPFD (or PAR) measurements. Some Apogee quantum meters (Logan, Utah, USA) offer the option of 'sun' and 'electrical' measurements leaving the hobbyists wondering which to choose. After comparing the Apogee's measurements to those obtained by a 'lab-grade' quantum meter (Li-Cor Biosciences, Lincoln, Nebraska, USA), I recommend using the 'sun' mode.

Options

At the time of this writing, Build My LED offers three pieces of optional equipment. One is a dimmer switch (capable of dimming LEDs to 10% of total output and available for $39.99; See Figure 8) while another is a kit for hanging the luminaire from the ceiling; $24.95). A recently available option is a kit for attaching the fixture to the aquarium and allowing you to aim it (available for $14.99).

Pricing and Ordering

At the time of this writing, a 12" luminaire is priced at $119, a 24" at $179, the 36" at $229, and the 48" at $269 (discounts are available for multiple orders). Online ordering allows selection and submittal of all options - simply click-and-drag the LED options into the luminaire template, and click on other options. There is a tutorial for using the ordering portion of the website, but I found it unnecessary as the site is intuitive.

Website

www.buildmyled.com is one of the most impressive I have seen. Over the years, I have programmed more than a few Excel files for analyzing light and I can appreciate the amount of work this site has in it. For example, a few keystrokes can show you:

• Beam angle intensity map
• Lumens
• Micromoles
• Input watts
• CIE x-coordinate
• CIE y-coordinate
• Electrical watts
• Radiometric watts
• Correlated Color Temperature (CCT, where applicable)
• Color Rendition Index (CRI, where applicable)
• Operating Temperature
• Predicted Life
• Spectral content (%blue, green, red, far red)
• Spectral content at various depths in an aquarium

Certifications

All products meet RoHS (Restriction of Hazardous Substances) requirements and are CE (Conformité Européenne) certified for distribution within the European Union.

Warranty

Build My LED offers a 3 year warranty.

Customer Service

Customer service before and after the sale is an important consideration. Co-owner Nick Klase has taken time from his busy schedule to answer my questions. I am impressed with the depth and breadth of his lighting knowledge. It has been my experience that delivery (from Texas to Hawaii) takes about 7 days (very quick considering the luminaire is custom built).

Testing Protocol

Spectral characteristics of the LEDs were measured with an Ocean Optics fiber optic spectrometer. Kelvin and Color Rendition Indices (CRIs) were determined through use of Ocean Optics' SpectraSuite software after the spectrometer had been calibrated to a LS-1-Cal 2,800K halogen-tungsten light source. Photosynthetic Photon Flux Density (PPFD, 400-700nm) was measured with a Li-Cor 1400 quantum meter/datalogger equipped with an underwater quantum sensor (calibrated to 'air') , while underwater measurements were taken with an Apogee quantum meter.

Reference

1. Jeffrey, S., R. Mantoura, and S. Wright, 1997. Monographs on Oceanographic Methodology: Phytoplankton Pigments in Oceanography. United Nations Educational, Scientific and Educational Organization (UNESCO). Paris, France. 661 pp.

It was 2005 when I last wrote an article presenting results of a comparison between Photosynthetically Active Radiation (PAR) meters, and the lamps used during testing were metal halides of various kelvin ratings (see Riddle, 2007). In those days, the use of light-emitting diodes (LEDs) for aquaria was something discussed by only a few. Nowadays, use of metal halide lamps is much less popular and usually seen over larger aquaria or those of die-hard fans, yet, to my knowledge, there have been no updates on the utility of different brand PAR meters and their responses when judging output of LEDs.

This article will compare the responses of three quantum meters when measuring LED light output. Specifically, these are meters manufactured by Apogee Instruments™ (model QMSW-SS; Logan, Utah), Li-Cor Biosciences™ (LI-1400 datalogger and LI-189 sensor; Lincoln, Nebraska) and Spectrum Technologies™ (FieldScout; Plainfield, Illinois).

Product Details

Li-Cor LI-1400 Quantum Meter and LI-189 Sensor Li-Cor Biosciences (Lincoln, Nebraska, USA) is noted for quality instruments, and their meter/sensor combinations have gained wide acceptance within the scientific community. Quality comes at a price (the referenced combination currently costs more than $3,000). The sensor construction is an intricate one - see Figure 1. In addition, the sensor is relatively large and the cord exits the bottom. These facts restrict its use to larger aquaria.

Apogee Quantum Meter Apogee Instruments (Logan, Utah, USA) manufactures entry-level PAR meters and sensors, and many hobbyists have found favor with them due to their affordability. The sensor is relatively small and its cord exits the side making it ideal for use in tight quarters (such as aquaria).

FieldScout Quantum Meter Spectrum Technologies (Plainfield, Illinois, USA) manufacturers a number of products aimed at the agricultural/horticultural markets. Although the meter tested here is the FieldScout Light Meter, the sensors are interchangeable with other Spectrum products (such as their wonderful WatchDog datalogger). The sensor tested here was custom-built for my lab for use when testing artificial light sources. Spectrum does not recommend their quantum sensor for use with LEDs but I wondered just how much of an error there actually is, hence I have included it in this review.

In all fairness, we're comparing an expensive instrument (the Li-Cor setup costing over $3,000) to relatively inexpensive ($300-$400 or so) units. A calibrated light source would be needed to accurately judge the responses of all three meters. This luxury was not available for this review, hence the Li-Cor meter - based on the advertised responses of all three meters - will be considered 'correct'.

There are several things that can affect a quantum meter's reading, these include:

• Spectral sensitivity of the sensor
• Spectral quality of the light
• Sensor Cosine Correction
• Sensor Construction (2 pi or 4 pi)
• Testing medium (air, water, etc.)
• Condition of the sensor (physical damage, age - 'fogging' of optical components, cleanliness)
• Sensor/meter calibration
• Temperature
• Light source used for calibration by the manufacturer

These terms will be used throughout this article:

Glossary Actinity Error: A perfect PAR sensor would be equally responsive to all wavelengths of light between 400nm and 700nm. In practice, this is not possible and response difference between a real sensor and a theoretical one is called the actinity error. Various sensors over- or under-report blue wavelengths while red wavelengths are often under-reported.

Correlated Color Temperature (CCT): is a specification of the color appearance of the light emitted by a lamp relating its color to the color of light from a reference source (a blackbody) when heated to a particular temperature, measured in degrees Kelvin (K). The CCT rating for a lamp is a general "warmth" or "coolness" measure of its appearance. However, opposite to the temperature scale, lamps with a CCT rating below 3,200 K are usually considered "warm" sources, while those with a CCT above 4,000 K are usually considered "cool" in appearance.

Cosine Correction: A light sensor should be able to accurately measure light at angles to ~90 of normal incidence (0), and a cosine-corrector allows this. Two cosine-correction types exist - one type is a hemispherical plastic diffuser dome (used by Apogee and Spectrum Technologies), while the other is a plastic cylinder (that should rise slightly above its housing in order to properly collect light, which the Li-Cor sensor does).

All sensors are advertised to be cosine-corrected, meaning their response will be the same to a beam of light, regardless of that beam's angle of incidence to the sensor (up to a point. Li-Cor advertises their sensor to be correct for light falling at an 80 angle from normal while Apogee states their sensor is ±1% at a 45 angle (from zenith) and ±5% at a 75 degree angle from zenith).

Full Width Half Maximum (FWHM): This is an important concept in light measurement. It is simple and easily defined. While the spectral width of the light source could extend for some distance, the maximum is easily determined as is the half-maximum. FWHM is generally used to define peaks and half-maxima of relatively narrow bandwidths (such as LEDs and other 'specialty' cases such as fluorescence). See Figure 2.

FWHM is not used for broadband light sources (such as sunlight and most artificial light sources). Let's take an example of why FWHM is important. See Figure 14 - it is the spectral characteristics of a combination of blue and white LEDs. This example would share the FWHM characteristics of a blue LED while ignoring the full spectrum characteristics.

Immersion Effect: Reflection of light within a sensor immersed in water is less (relative to a measurement made in air) and results in a greater loss of light. This is due to the refractive indices of plastic and air or water. Hence, more expensive devices (such as the Li-Cor) allow for an 'air' or 'water' calibration to overcome the immersion effect. The Apogee and Spectrum Technologies meters do not offer this option.

Integrating Sphere: A device used in measuring light and especially useful when determining flux or spectra of LEDs. Basically, it is a hollow sphere with a diffusive interior coating. Two ports (one for the LED and the other for a light sensor) are at a 90 angle to one another.

Lambertian Reflectance: Diffuse reflectance is that which appears to be of the same brightness regardless of the observer's viewing angle. Labsphere's Spectralon (a fluoropolymer) offers an almost ideal Lambertian surface. Barium sulfate is a less expensive - but less Lambertian - material.

Light-emitting Diode (LED): A light emitting device consisting of a positive/negative junction where a small amount of electrical current excites metallic compounds doped on a small 'cup'.

Photosynthetically Active Radiation (PAR): Light energy powers photosynthesis. This light's bandwidth has been standardized to that electromagnetic energy between 400 and 700nm (violet to red) per area unit (often 1 square meter) per time unit (usually 1 second). PAR is reported as Photosynthetic Photon Flux Density (PPFD) in units of micromole photons per square meter per second (µmol·m²·sec).

Reflectance: The ratio of the total amount of radiation, as of light, reflected by a surface to the total amount of radiation incident on the surface.

Two pi Sensor; Four pi Sensor: Sensors that collect light only from the direction the sensor is pointed is called 2 pi. A scalar sensor collects light from all directions. A 4 pi scalar sensor resembles an incandescent light bulb. See Figure 3.

Spectral Responses of Three PAR Sensors

Understanding the spectral sensitivities of different PAR sensors is helpful in understanding how accurate measurements will be, especially when dealing with narrow bandwidth light sources, such as LEDs. For our purposes, there are two types of sensors - silicon and gallium arsenide phosphide (GaAsP). The Li-Cor sensor is the silicon type, while the Apogee and FieldScout sensors appear to be made of gallium arsenide phosphide. Figure 4 shows the spectral sensitivity of the Apogee meter, Figure 5 the FieldScout's, and Figure 6 that of the Li-Cor. Unfortunately, Spectrum Technologies does not provide the relative ideal response of their sensor and we therefore must make some assumptions about the actinity errors. Figure 7 is a side-by-side comparison of the Apogee and Li-Cor responses.

The Apogee meter apparently uses a gallium arsenide phosphide (GaAsP) based sensor with a lens/filter in order to slightly correct the sensor's response. However, it is generally agreed that this type of sensor underestimates violet/blue light (400-500nm) and red wavelengths above 650nm.

Effects of Temperature

Apogee's calibrates their quantum sensors at 68F (20C). It reads 0.6 percent high at 50F (10C) and 0.8 percent low at 86F (30C) - see Figure 8. Li-Cor states a change of ± 0.15% per °C (maximum).

Relative Humidity

When making sunlight measurements, the amount of water vapor (humidity) in the atmosphere can cause lower than expected readings. See here for details:

http://clearskycalculator.com/model_accuracyPPF.htm#RH

Note that all reported measurements were made in the air and the impact of the ultimate humidity - water - will impact meters' responses.

'Sun' and 'Electric' Measurements

In the models tested here, Apogee and Spectrum meters offer two measurement modes to overcome deficiencies in the spectral responses of their sensors. Testing revealed that, on average, there is a difference of about 10% between the two modes. However, spectral quality decides which mode is best for a given light source.

Our testing begins with:

Response of Meters to Sunlight

Figures 9 and 10 show the meters' responses to broadband light energy (sunlight, during an overcast morning) and the spectral quality of that light, respectively. As we can see, all meters do a reasonable job of reporting PPFD.

Response of Meters to Individual LEDs

As we have seen, each of the PAR meters have done a reasonable job of reporting PAR values of sunlight, even though their sensors' spectral sensitivities vary dramatically. Results of LED testing will now be presented.

Blue LEDs

Blue LEDs are ubiquitous in lighting designed for reef aquaria and are often combined with LEDs emitting 'white' light ('white' LEDs are blue LEDs to which a phosphor has been added. This phosphor absorbs some of the blue light and fluoresces it in a broad spectrum). Two blue LEDs were examined. See Figures 11 and 12 (notice the differences in the FWHM of the two).

The following Figure (13) shows the PAR measurements of the Acan blue LED.

Blue/White LED Combination

This combination of LEDs is perhaps the most popular among reef hobbyists, although the ratio of white to blue varies. Figure 14 shows the spectral characteristics of Acan Lighting's LED luminaire (ratio of 2 cool white to 1 'royal' blue).

White LEDs

When comparing the spectra of blue and white LEDs, it is easy to see the effects of the phosphors added to a blue LED (these phosphors are the same as those used in broad spectrum fluorescent lamps). White LEDs are often used in combination with 'pure' blue LEDs to mimic the blueness of deeper oceanic waters. See Figure 16.

Cyan (or Aqua) LED

Those manufacturers specializing in reef aquaria lighting have recently begun adding variously colored LEDs to their luminaires (interestingly, the first commercially successful LED luminaire, made by PFO Lighting) used green LEDs in addition to blue and white ones). Use of cyan LEDs has a basis when we examined zooxanthellae photo-pigments. Chlorophyll a is sometimes bound with another photo-pigment - peridinin. This complex absorbs light into the green portion of the spectrum and makes it available for photosynthesis. See Figures 18 and 19 for a spectral characteristics and PAR measurements of a cyan LED, respectively.

Green LED

Many of the comments made about the cyan LEDs would apply to the green LED examined here. The chlorophyll a/peridinin complex can absorb the light emitted by this LED. See Figures 20 and 21.

Yellow LED

Yellow light is only weakly absorbed by zooxanthellae photo-pigments; however, there is some evidence that yellow light plays a part in intensifying the apparent fluorescence of some orange/red coral pigments. See Figures 22 and 23 for results of testing.

Red LED

Of all the LEDs examined here, those emitting red light are the most controversial. Very little red light is found at depth on natural reefs and it would seem that use of white LEDs (emitting some red light) would satisfy the visual requirements of the hobbyist while supplying more than enough red for photosynthesis. See Riddle, 2003 for effects of too much red light. I'm presently working on the assumption that if a lot of red light is harmful to zooxanthellae, then a lesser amount is proportionally harmful. I am just beginning a project to investigate red light's impact. This will be a part of my presentation at the 2103 MACNA in Florida (www.masna.org).

See Figures 24 and 25.

This completes our observations and analyses of PAR meters and LEDs. Now for our conclusions.

 

Conclusion and Recommendation

I decided to write this article after hearing anecdotal comments such as 'PAR meters are useless for measuring LED output' and 'Corals don't survive long-term under LEDs'. The latter has not been my experience, but I really had no idea about the former statement. The concept for this article seemed valid enough and I suspected the article could be written in short order. I had the meters and the LEDs and making the measurements could be made quickly - or so I thought. After writing almost 300 articles for hobbyist-related publications over the course of over 25 years, one might think I would have a good handle on the complexity of a project. In this case, I thought I could research and write the article in 2 or 3 weeks. As it turned out, this work required months of research, construction, measurement, and analyses. The results are complex. To reiterate, we're comparing two relatively inexpensive meters against one costing roughly 10x as much. When measuring sunlight, the Apogee and Spectrum Technologies meters report PAR values that compare favorably to those of the Li-Cor. Additionally, Spectrum Technologies states on their website that their sensor is not useful in making measurements of LEDs (a bit of an overstatement as we shall see).

This product evaluation took on added complexity when we consider two of the meters offer two measurement modes - in essence, we are comparing 5 meters, not three. The Apogee and Field Scout meters offer the option of two measuring modes ('Sun' and 'Electric'). This is done in order to offset limitations of the spectral sensitivity of their sensors. The more expensive Li-Cor sensor and meter has no reason to offer this option due to the superior spectral response.

Interestingly, the difference in 'Sun' and 'Electric' measurement modes is almost always about 10% (suggesting the difference is simply the result of a preset electronic correction). However, this correction cannot overcome the ability of the sensor to 'see' light. Therefore, Table 1 is offered for those wanting to measure narrow bandwidth light sources such as LEDs.

Table 1. Recommended Meter Settings for Various Light Sources. 'X' marks the recommended setting ('Sun' or 'Electric' for the LEDs tested, and 'High' or 'Low' indicate the direction of variation from the reading made by the Li-Cor meter and sensor. The measurement was essentially the same as the Li-Cor product if the box is marked with only an 'X'.

	Apogee		Field Scout
LED	Sun	Electric	Sun	Electric
Blue (450nm)	X	Low	X (Low)	Low
Blue/White Combo	X (Low)	Low	High	X (High)
White (7,300 K)	X	Low	High	X (High)
Cyan (505nm)	High	X (High)	High	X (High)
Green (517nm)	High	X (High)	High	X (High)
Yellow (595nm)	X (Low)	Low	High	X (High)
Red (647nm)	X (Low)	Low	High	X (High)
Sunlight (Mostly Sunny)*	High	X (High)	High	X (High)
*Sky Conditions and Sensor Response: As even the most casual observer knows, sky conditions can drastically alter its apparent color composition. The most obvious examples are the yellow 'morning' and orange 'sunset' colors. However, more subtle effects are in play during the day. 'Cloudy' refers to the blue sky and sun being hidden completely by opaque clouds. 'Sunny' conditions exist when no clouds are present. A 'mostly sunny' sky is obscured by no more than 2/8ths opaque clouds. 'Partly sunny' and 'mostly cloudy' means 3/8 to 5/8ths and 6/8 to 7/8ths opaque clouds, respectively. The term 'clear' (as opposed to sunny, naturally enough) is used for nighttime observations. 'Fair' is not a useful meteorological term and should be avoided.

¹ The impact of volcanic smoke (vog) on the meters' performance is unknown. Although the measurements were made when conditions were considered to be 'mostly sunny', there is a certain haziness to the sky. Vog is known to absorb some ultraviolet radiation. In addition, there is a considerable amount of seawater aerosols in the air.

Simply using the manufacturer's sensor spectra response chart can lead to incorrect conclusions. There were some surprises. It seems to be current wisdom that the Apogee meter under-reports blue light, yet the results of testing showed the meter performed well when in 'sun' measurement mode (while the electric mode read low). Similarly, the Apogee did very well in 'sun' mode when analyzing the output of 7,300 K white LEDs. In addition, the Apogee and FieldScout meters repeatedly performed best when measuring sunlight when in the 'electric' setting.

Based on these observations, inexpensive PAR meter have some utility for measuring light produced by LEDs.

 

Lux to PAR Conversion Factors

If you have a lux meter, it is possible to convert lux measurements to PAR values. Use these results with some caution - in most cases it would be safe to assume the results will be low.

• Divide blue (450nm) LED Lux by 69
• Divide white (7,300 K) LED Lux by 45
• Divide blue (450nm)/white (7,300 K) combination LED (2:1 white/blue ratio) Lux by 67

 

Technical Notes

Spectral analyses were performed by Ocean Optics USB2000™ fiber optic spectrometer and SpectraSuite™ software (Ocean Optics, Dunedin, Florida). It took some doing to design and build a workable integrating sphere from scratch (on the order of weeks). Original prototypes were made of papier mâché and were large (6-inch, or ~150mm) diameter, then reduced to 3-inch (76mm). These proved to be too large and did not sufficiently concentrate light. Ultimately, ping pong (table tennis) balls were used. Their exterior were painted white and the interior of the hollow spheres were painted matte white and then coated with barium sulfate (ACS grade) in order to create a surface with good diffuse spectral reflectance characteristics. Barium sulfate was mixed with un-tinted white latex paint (90:10 weight: weight). Two 1/2" (12mm) holes were drilled into the sphere at a 90 angle. An interior baffle was placed adjacent to the sensor port to prevent light from falling directly upon it.

Barium sulfate is known to offer good reflectance at ~425 - 700nm. To check this, the barium coating was compared to a diffuse reflectance standard (Labsphere Spectralon WS-1-SL, a fluoropolymer offering a highly Lambertian surface with reflectivity of 99% at 400-1,500nm). See Figure 26 for the reflectance of the barium sulfate coating.

Figure 27 shows the integrating sphere.

The integrating sphere would not collect enough light in some cases. To overcome this problem, measurements were made of the high intensity output of a LED luminaire manufactured for aquarium use (Acan Lighting, model 600-18B, Commack, NY). See Figure 28.

Determination of Correlated Color Temperature (CCT) was determined with an Ocean Optics USB 2000 spectrometer and SpectraSuite software. In order to do so, the spectrometer's measurements must be calibrated to a known source. To this end, an Ocean Optics' LS-1-Cal tungsten halogen NIST-traceable light source was used. This light source had little use on it and total hours fell well below the cutoff of 50 hours (when re-calibration is required). Settings of the software included a setting for 'emissive' color (that emitted by a light source such as a LED) and 2 Observer (photopic, daylight observer).

Lux measurements were made using a Gossen Luna Pro lux meter (Gossen Foto-und Lichtmesstechnik GmbH, Nürnberg, Germany).

 

Calibration

Apogee recommends calibration of their meters ever 3 years, while Li-Cor recommends every 2 years. The Apogee meter has not been calibrated since purchase. The Li-Cor LI-1400 data logger is new and its sensor was rebuilt about 5 years ago.

To check if your PAR meter needs re-calibration, see this site:

http://clearskycalculator.com/longitudeTZ.htm

Note: This calculator works if the sky is truly clear. It did not perform well here in Hawaii due to the amount of 'vog' from the continuing volcanic eruption.

 

References

1. Kirk, J.T.O., 2000. Light and Photosynthesis in Aquatic Ecosystems. Cambridge University Press, Cambridge, United Kingdom. 509pp.
2. Riddle, D., 2005. Product Review: A Comparison of Two Quantum Meters- Li-Cor v. Apogee. http://www.advancedaquarist.com/2005/7/review
3. Riddle, D., 2003. Effects of narrow bandwidth light sources on coral host and zooxanthellae pigments. http://www.advancedaquarist.com/2003/11/aafeature

New LED fixtures continue to be introduced into the hobby. Specifically, there is an increase in the number of LED fixtures providing a more fuller color spectrum with multiple channels of control, allowing the user more freedom in custom tuning the light output. Continuing in the same vein as my previous LED lighting tests, this article presents data on light intensity and spread along with spectral plots for several new LED fixtures. Table 1 presents a list of the LED lighting fixtures reviewed in this article. Each of these was tested using the same set up as my previous reflector tests, using a 3'X3' grid with a spacing of 3" in the X,Y direction. The fixtures were centered on this grid, and PAR was measured as PPFD (Photosynthetic Photon Flux Density) in micromoles/m²/sec using a LICOR 1000 data logger and a LI-192SA underwater cosine corrected sensor calibrated for both air and water. The data logger was set to average 5 readings for each data collection point. The data was imported into Microsoft Excel for analysis and the data was plotted to display the light spread and intensity at various distances. 4 plots of the data with 2 plots at each distance were generated showing:

• A 3-D surface plot showing the actual PAR values recorded
• A contour plot viewing the surface from the top showing the distribution

The spectral distributions were measured using the Licor LI-1800 spectroradiometer. The spectral data was collected from the various LEDs and normalized such that integrated light output (spectral irradiance) between the wavelengths of 400-700 nm was 100 Watts/m². Data was collected at full power output for the individual channels of light control (eg. Blue, white) along with data with ALL LEDs on at full power. The data was normalized so that the full output was at 100 Watts/m² over the wavelength range 400-700 nm. The various LED color outputs were then scaled by the same scale factor to allow of determination of the contribution of the various LEDs to the full output. The results are plotted as a Spectral power distribution plot.

Table 1: LED Lighting Fixtures Tested

LED Fixture	Picture
AquaIllumination: AI-Vega
Maxspect Mazarra-P

The fixtures were tested for light spread and intensity at 24"and 30", unless otherwise noted. Power draw was measured with a Kill-A-Watt meter.

Maxspect Mazarra P-series

The Mazarra P series is a modular lighting system that is sold as a complete unit with LED modules, frame mounts, power supply, and controller. The modular design allows for the addition of additional LED modules, on a support frame that is adjustable to fit a wide range of aquarium sizes. The mounting of the LED modules allows for sliding the location of the LED modules as well as allowing the LED modules to be mounted at an angle. The ability to adjust angular orientation allows for better control in directing the light output. It addition to the flexibility in mounting, this lighting fixture also allows for a plug and play replacement of the LED bulbs and the optics. 100, 70 and 40 degree optics come standard with the modules. The controller provides 4 dimmable channels, and each controller can control 16 LED modules. The LEDs used in each module are Cree XLamp XM-L, Philips Luxeon Rebel, Epileds Dual-Core, and Cree XLamp RP-G LED chips. As per the specification, each LED module is rated as 60W (4-Cree XLamp XM-L 7000-8000K @ 1500mA, 4-Philips Luxeon Rebel 460-490nm @ 1000mA, 4-Philips Luxeon Rebel 440-460nm @ 1000mA, 1-Epileds Dual-Core 400-410nm @ 1000mA, 1-Epileds Dual-Core 410-420nm @ 1000mA, and 2-Cree XLamp XP-G 3000K @ 1000mA).

AquaIllumination AI - VEGA Color

The AI-Vega is the next generation LED light fixtures from Aqua Illumination. Compared to their previous products, popular AI-Sol and Sol-Blue, the AI Vega offers additional LED colors and 6 channels of control. Each LED fixture comprises the following LEDs:

• 4-Cree XM-L Cool White
• 4 - Cree XP-E Royal Blue
• 4 - Cree XP-E Blue
• 4 - OSRAM OSLON Deep Blue
• 2 - Cree XP-E Green
• 2 - OSRAM OSLON Deep Red

A wireless controller allows for infinite control of the 6 lighting channels to create a wide range of color combinations, along with programing in special effects such as clouds and lightning.

Conclusions

As LED lighting moves further into the mainstream, there is new effort being made to provide a fuller spectrum light that can be tuned by the aquarist to satisfy both the demands of the corals as well as the visual pleasure of the aquarist. Hopefully this data will help the aquarist make an informed choice on what to expect from the individual LED fixtures and how best to utilize them to achieve the desired coverage and light intensity.

The art and science of reefkeeping continues its steady progression with introductions of equipment that we only dreamed about in the hobby's early days. Early on, it was recognized that lighting was critical while water motion received relatively little attention. Since the reef hobby was such a tiny fraction of the aquarium trade, few manufacturers were catering to the needs of reefers so hobbyists were forced to improvise. Serious hobbyists were handcrafting dump buckets and siphon-based Carlson Surge Devices. One dedicated aquarist, Jimmy Chen, modified a Little Giant™ pump by adding a model boat propeller. This ingenious concept would have far-reaching ramifications and eventually revolutionized the way we move water in reef aquaria.

After years of sitting on the sidelines, Marineland finally decided to get into the propeller pump business and now offers Maxi-Jets in three configurations: Propeller Pump, Powerhead, and Utility Pump, all available in a single package marketed under the name of Maxi-Jet Pro. These new designs and configurations call for another in-depth look at their performance. How will the New Maxi-Jets compare against the old?

Marineland Aquarium Products' Maxi-Jet pumps have been around for quite some time. These pumps, with their epoxy-encapsulated motors proved to be highly reliable and became workhorses within the hobby. Recently, their design changed as well as their country of manufacture. The original Maxi-Jets were imported from Italy; they are now made in the Peoples' Republic of China. Although similar in appearance, the new pumps are slightly different and parts are not interchangeable between the new and old designs. The manufacturer promises relatively high performance while offering them at very modest prices. Is this a case of 'you get what you pay for' or are they a true value?

Manufacturers' Specifications

These specifications are current at the time of this writing:

Maxi-Jet Powerheads

• Maxi-Jet 400 Pro Powerhead
  • Advertised Flow (gallons per hour/liters per hour): 110/416
  • Impeller Diameter: ~13/16" (21mm), 6 vanes, tan plastic impeller
  • Discharge Diameter: ~1/2" (12mm)
• Maxi-Jet 600 Pro Powerhead
  • Advertised Flow (gallons per hour/liters per hour): 160/606
  • Impeller Diameter: 1-1/8" (29mm), 6 vanes, red plastic impeller
  • Discharge Diameter: ~1/2" (12mm)
• Maxi-Jet 900 Pro Powerhead
  • Advertised Flow (gallons per hour/liters per hour): 230/871
  • Impeller Diameter: 1" (25mm), 6 vanes, yellow plastic impeller
  • Discharge Diameter: ~1/2" (12mm)
• Maxi-Jet 1200 Pro Power head
  • Advertised Flow (gallons per hour/liters per hour): 295/1,117
  • Impeller Diameter: 1-3/8" (35mm), 6 vanes, purple plastic impeller
  • Discharge Diameter: ~1/2" (12mm)

Maxi-Jet Propeller Pumps

• Maxi-Jet 400 Pro Propeller
  • Advertised Flow (gallons per hour): 500
  • Number of Blades: 2 (gray plastic)
  • Propeller Diameter: 1-1/4" (33mm)
  • Discharge Diameter: 1-11/16" (43mm)
• Maxi-Jet 600 Pro Propeller
  • Advertised Flow (gallons per hour): 750
  • Number of Blades: 2 (white plastic)
  • Propeller Diameter: 1-3/8" (43mm)
  • Discharge Diameter: 1-11/16" (43mm)
• Maxi-Jet 900 Pro Propeller
  • Advertised Flow (gallons per hour): 1,000
  • Number of Blades: 3 (gray plastic)
  • Propeller Diameter: 1-7/16" (37mm)
  • Discharge Diameter: 1-13/16" (47mm)
• Maxi-Jet 1200 Pro Propeller
  • Advertised Flow (gallons per hour): 1,300
  • Number of Blades: 3 (white plastic)
  • Propeller Diameter: 1-1/2" (39mm)
  • Discharge Diameter: 1-13/16" (47mm)

Flow Rates - Advertised versus Actual

How much water pumps move is often a prime factor when considering a purchase. Tests were performed according to methods listing in Testing Protocols (below). How do these pumps' advertised flow rates stack? See Figures 1, 2, and 3.

Flow Attenuation

The weakening (attenuation) of flow over distance is an important, but often overlooked, concern. Simply looking at the number of gallons pumped per hour or discharge velocities fails to tell the whole story. Knowing at what distance the flow drops below a certain point is valuable information when decided how many pumps to use. On a natural coral reef here in Hawaii, flow velocity is normally about 4 inches (0.25 feet) per second, hence we'll use that figure as a cutoff point. As Figure 4 shows, flow velocity drops below 4 inches per second at a distance of about 17-18 inches from the Maxi-Jet 400 pump's discharge.

Figure 5 shows us a Maxi-Jet 1200 propeller pump can push water at a velocity of 4 inches per second about 24 inches from the pump's discharge.

Power Consumption: Powerheads, New & Old, and Prop Pumps

Reefkeeping is not known as a particularly inexpensive hobby. After initial setup and livestock purchases, there are monthly maintenance costs to consider. Power consumption is usually tops the list of routine expenses. See Figures 6 and 7.

Powerhead Power Consumption - Old versus New

The new Maxi-Jet powerheads (made in China) draw more power than the old powerheads (Italian made). See Figure 8.

Power consumption is only part of the story. To be objective, efficiency must be estimated. In order to do this, amount of water pumped was divided by watts. See Figure 9.

Mounting Hardware

The Maxi-Jet Pro box comes packed with various pieces for the three different pump configurations. One of these - a mount with suction cups - can be used with all three. When used to mount the pump to the floor of an aquarium, it will work just fine. Using the suction cups on a vertical surface is a different story. It is only a matter of time before the suction cups lose their grip and allow the pump to fall. Another piece included is a hanger with articulated joint called an omni-directional mount. I found the ball-and-socket friction fit to be sloppy and it would not keep the pump in position. There is an inexpensive fix - once the desired position is determined, a drop of Super Glue on the ball-and-socket joint will weld it in place. I would personally prefer that the new joints were as tight as the old ones. Obviously a flexible joint allows a lot of latitude.

Compatible with Sure Grip Magnets

The new Maxi-Jet omni-directional holder design is compatible with Sure Grip magnets. The magnets are expensive relative to the cost of the pump, they're a good investment considering the investment you've got in livestock.

Noise Pump & At Start-Up

Maxi-Jet pumps operate on alternating current (AC) and this presents some engineering challenges for the propeller pumps. The propeller must spin in the proper direction to push flow into the aquarium. This is a problem with alternating current - at start up, the prop may or may not spin in the correct rotation. To overcome this issue, engineers have incorporated a ratchet-like device at the end of the propeller's axial shaft. If the prop turns the wrong way, it pushes itself into this ratchet stop and once movement is arrested, it should start to spin correctly and pushes itself away from the stop device. Simple and usually effective but there is a downside - when the prop engages the stop, it makes a chattering noise until it begins to rotate correctly. This is one of the reasons why propeller pumps operating on alternating current are not recommended for use with wavemakers (there is also the possibility of damage to the prop assembly).

Noise is not much of an issue when the Maxi-Jet is used in the powerhead or utility pump configurations. The impeller can spin in either direction and still push water. Powerheads can be used on wavemakers.

As mentioned, the propeller volute is held on the motor housing by friction fit. There is a chance that vibration will make a low humming noise if the volute is not properly fitted to the housing.

Are New & Old Parts Interchangeable?

No. Parts of the old and new design are not interchangeable. Any post-market propeller modifications will not work with the new design.

Electrical Cord Length

The four pumps examined here have a cord length of 72 inches (~1.83 meters). Although this detail may seem trivial, it is not. Generous cord lengths (as we have here) are a plus when used with larger aquaria or when dealing with distant power outlets. It is especially important in making 'drip loops' to prevent water from migrating to an electrical outlet.

Comments

Likes:

• Price. If you can't afford these pumps, you should consider a hobby other than reefkeeping.
• Flexibility. These pumps can meet many demands - they can run reactors, small skimmers, and can mix smaller batches of artificial seawater, plus move enough water in smaller reef tanks.
• Marineland's advertising claims generally underestimate their products' performances. The 400, 600, and 900 powerhead models exceed advertised pump rate claims and the 1200 almost exactly matches their flow estimate.
• These new models pump more than the older Italian-made units so it is not surprising that these 'new' Maxi-Jets consume more power. The propeller pumps also exceed the amount of water pumped as claimed by the manufacturer.
• These pumps are listed by Underwriter's Laboratories.
• The new 1200 powerhead is more energy efficient than the older (Italian) model.
• Mounting hardware is compatible with at least one post-market magnet (such as Sure Grip).

Dislikes:

• The friction fit of the omni-directional mount is sloppy and does not hold the powerhead/prop pump in position. Although a fix is simple (a drop of Super Glue will fix the mount in place), I'd rather see tighter tolerances to allow on-going latitude in positioning.
• The shroud for the propeller pump must be carefully placed to allow proper alignment with the propeller assembly's axial shaft. There will be vibration if there is a lot of misalignment. I have heard reports of the propeller housing coming loose and 'blowing off'. I didn't see this during testing and feel the friction fit of the housing to the pump motor is enough to hold it in place. It is possible that misalignment and resulting vibration could be to blame for the housing coming off. If misalignment is relatively minor, no vibration is apparent and it's possible that flow output will be reduced. I had problems getting proper alignment on the 1200 and reduced flow was not apparent unless I checked the power draw with a watt meter, or determined flow velocity with an electronic water velocity meter.
• Suction cup mount for vertical surfaces. These invariably become detached.
• The new 600 and 900 model powerheads are less energy efficient than the older model powerheads.
• No foam covers to keep foreign particles from entering the prop pumps are offered.

Recommendations

Based on flow attenuation data presented above, two or more of the propeller pumps should be adequate for smaller reef aquaria (up to ~20 gallons). More should be used for larger tanks. Do not use the propeller pumps with fishes that 'pick' such as Chelmon butterflies (or any of the longnose butterflies) - they whirling motion of the moving prop attracts their attention. Disaster awaits when their snouts meet the propeller.

These pumps are not perfect and the propeller versions suffer from some design issues, however, they perform as advertised or better, and the price makes them attractive to budget-minded hobbyists sensitive to the cost of the pump.

Warranty

Marineland Aquarium Products warranties these pumps for 2 years after date of purchase, and will repair or replace defective parts at their option. See www.marineland.com for details.

Testing Protocol

All pumps were tested in a 240-gallon test tank (8'x2'x2') filled with saltwater at a specific gravity of 1.025. Water velocity was measured with an electronic water velocity meter (FloMate 2000 made by Marsh-McBirney, Frederick, Maryland, USA). Velocity was plugged into this formula (Flow=Velocity x Area) in order to determine flow rate of gallons per hour. Electricity consumption was monitored by a Kill-A-Watt power meter made by P3, International.

While a great deal of interest has been shown in the characteristics of artificial daylight for reef aquaria, very little attention has been paid to the other natural illumination - moonlight. Although manufacturers have marketed moonlight simulators for a number of years, I've yet to see an in-depth discussion of the subject. This article will attempt to address that issue while discussing some misconceptions about lunar light. In addition, we'll define spectral characteristics of moonlight, light intensity, and length of natural lunar photoperiod, and ways to simulate moonlight. We'll also examine the effects (or non-effects) of moonlight on timing of coral spawning (and comment, albeit briefly, its effects on fish spawning behavior).

Lunar Photoperiod in Hawai'i

As we know, the lunar cycle consists of 29.5 days and is the basis for our calendar month. The lunar phase changes in a predictable manner and is due to relative positions of the moon, earth, and sun. Phase is not due to the earth's shadow falling upon the moon (this is referred to as a lunar eclipse). Figure 1 shows phases and approximate and approximate days of the lunar month.

Figure 2 shows the hours of potential moonlight in Hawaii. Data are based on times of sunrise/sunset and moonrise/moonset.

Moonlight Spectral Characteristics

Since moonlight is almost entirely reflected sunlight, one might reason that the moon's spectral signature is exactly that of sunlight - it is not. Data shown in Figures 3 & 4 reveal that moonlight is less blue and redder than sunlight (and this measurement was taken with a 'silvery' moon at its zenith. We often see a much more orange moon at moonset).

Moonlight Intensity

Moonlight intensity is determined by lunar phase and sky conditions. Figure 5 shows moonlight intensity (in lux) under ideal conditions. Figures 6 and 7 show full moon light intensities (PAR) as measured during two nights (just a few feet above sea level). Note that the intensities are lower than that reported by Jokiel (0.05 µmol·m²·sec, or about 1 lux). The low moonlight intensity reported here is due to a number of factors, including seawater aerosols in the air, thin high level clouds, and vog (a mixture of atmospheric moisture and volcanic smoke from the Pu'u O'o vent and Halema'uma'u caldera of the Kilauea volcano).

Factors Influencing Coral Reproduction - Order of Importance

Moonlight is but one factor influencing coral reproduction. If other factors (nutrition, physical parameters, etc.) are correct, these are believed to be important:

Temperature: Temperature seems to exert powerful control over coral reproduction. If the temperature is too high, coral health can suffer, while cool temperature may delay spawning until the next month's window (Hunter, 1988; Riddle personal observations). Temperature has been stated to be the influence of paramount importance in the reproductive cycles of marine invertebrates (Olive, 1995). In Hawaii, the temperature threshold is about 75F (24C; Dr. Paul Jokiel, personal communication).

Moonlight: Lunar cycles set the date of spawning in many coral species and the lunar calendar can be used to accurately predict it.

Daylight Photoperiod: Solar photoperiods influence coral reproductive efforts and set the hour and minute of spawning (Vize et al., 2008). The time of sunset is the fine-tuning factor for many marine invertebrates including at least some sponge and coral species.

Corals Don't Have Eyes - How Do They Sense Light? And What Do They See?

Gorbunov et al. (2002) found blue light at about 480nm (110nm width, half maximum) at very low light intensity caused a reaction among coral tentacles,although a description of photoreceptors involved was not part of the experiment.

In 2003, Levy et al. exposed corals (azooxanthellate Cladopsammia gracilis) the bubble coral Plerogyra sinuosa, the flower pot coral Goniopora lobata, Favia favus, and Stylophora pistillata) to various light wavelengths (400-700nm at 20nm intervals) and intensities (10µmol·m²·sec and 30 µmol·m²·sec; ~500 lux and 1,500 lux, respectively) and recorded tentacle contractions. Cladopsammia did not respond to any light treatment, while Plerogyra sinuosa and Favia favus contracted their tentacles when exposed to wavelengths between 400-520nm (violet-blue-green). Interestingly, Favia favus also responded to red light (660-700nm) at 30 µmol·m²·sec or ~1,500 lux (see light sensitivities of rhodopsin-like compounds and cryptochromes below).

Five years later, a rhodopsin*-like compound was found in the stony coral Acropora millepora (Anctil et al., 2007), explaining how corals sense light. Almost simultaneously, Levy et al. (2007) described cryptochrome** proteins sensitive to blue light in Acropora millepora. Other researchers have noted corals' responses to light suggesting rhodopsin-like compounds are found in at least some corals.

This ability to sense light explains how corals can grow towards light, and if overturned, can redirect their growth (this is call phototropism). It also explains how corals set their biological clocks through sensing daylight and moonlight.

*Rhodopsin is a photosensitive pigment found in many animals' eyes (including humans) within receptors called cones. Cones and their rhodopsin content enable us to see in very low light conditions. Rhodopsin collects light in wavelengths of about 400nm (violet) to red (at ~600nmn) but most strongly in the blue-green portion of the spectrum (Hunt, 1987).

**Cryptochromes (Greek for 'hidden color') are proteins sensitive to blue light and are found in photoreceptors of plants and animals.

Entrained Biological Rhythms versus Response to Environmental Factors

The act of coral spawning involves production of a number of compounds, and this may be the result of entrained rhythms or exposure to external stimuli. For our purposes, entrained rhythms are those that occur without external stimuli such as sunlight or moonlight. These are likely controlled genetically. Environmental factors (such as like or moonlight) can influence the production of compounds. Vize et al. (2008) found photoreceptors signal production of proteins important in annual spawning of the stony coral Montastrea cavernosa.

Fish Reproduction and Lunar Phase

Many fishes are known to spawn synchronously around a certain lunar phase and this timing may be species-specific. For instance, Takemura et al., 2004 discuss lunar phase and spawning of the golden rabbitfish (Siganus guttatus). These fish did not spawn when subjected to constant illumination, and those held in conditions of total darkness at night displayed altered spawning patterns. Pressley (1980) described the relationship of lunar phase and reproduction of the yellowtail damselfish, Microspathodon chrysurus.

It is an interesting notion that circadian rhythms play an important part in fish reproduction and that accurate simulation of lunar phase may be an important factor.

Light Spectra Transmission in Clear Seawater

As mentioned earlier, several researchers have found that some corals respond to blue light. It is perhaps not by coincidence that maximum penetration of light occurs at about 480-500nm. See Figure 8.

Moonlight and Coral Spawning

Moonlight is commonly believed to be one of the deciding environmental factors for timing of coral spawning. Jokiel (1985) examined numerous Pocillopora damicornis specimens and concluded planula release occurred around the time of the full moon. However, Hunter (1988) experimented with two Hawaiian Montipora species (M. verrucosa = capitata and M. dilatata) and found the following:

• Both sets of corals spawned simultaneously with control corals when exposed to constant simulated moonlight (at a flux of 0.01 µmol·m²·sec, or about 0.5 lux)
• When exposed to no simulated moonlight (constant new moon), 43% of the M. verrucosa spawned in sync with the controls, and in the next month, 1 week prior to the new moon. Montipora dilatata specimens also spawned in synch with controls in the first month, and then 8 days out of normal phase the next month.
• When maintained under simulated moonlight shifted 14 days out of phase, both coral species spawned simultaneously with controls, and then 2 to 12 days out of sync in the second month.

Artificial Moonlight

It is usually impractical to expose an aquarium to moonlight hence artificial means are preferred. In my 1995 book, The Captive Reef, I outlined a means of simulating moonlight with a blue incandescent lamp and a manual dimmer. Technology has come a long way since then and light-emitting diodes are now the preferred method. See Figure 9.

Figure 10 shows the typical spectral quality of a LED peaking in the blue portion of the spectrum at ~450nm.

Controllers

There are a number of controllers on the market claiming to simulate timing and variable intensity of natural moonlight. This article is not intended to review all those available. Instead, I describe the one I own - the Tunze Multicontroller 7095. This device's main function is that of controlling Tunze pumps but includes a LED for moonlight simulation. The only thing a hobbyist has to do is turn the moonlight LED on when the real moon is full and the controller automatically does the rest. A photo-sensor will turn the LED moon on when the aquarium lights go out and lunar phase intensity is controlled over a 29 day cycle. See Figure 11 for a close up view of the photo-sensor/LED and Figure 12 shows the spectral characteristics of the LED.

In Closing

Many corals contain photoreceptors (note their ability to almost always grow towards light). Some demonstrate responses to blue light, while at least one species can sense both blue and red light. Some show no response to light.

Moonlight is thought to play an important role in timing reproductive cycles of many coral and fish species. In corals, lunar cycles set the date of spawning, while the time of onset of darkness fine tunes the cycle and decide the hour and minute (then a release of hormones into the water induces mass spawning). An altered lunar phase may at least temporary disrupt spawning synchrony among at least some coral species. Lunar periodicity seems to play a role in timing of reproduction among at least some fish species. Interestingly, short term exposure of some fishes to constant artificial moonlight may have prevented spawning, while the same did not affect the patterns in some corals. It seems apparent that different taxa are affected differently by altered moon phases, if only temporarily.

Although moonlight appears white or silvery, use of LEDs producing blue light to simulate moonlight is, at least for some coral species, correct based to peer-reviewed evidence. Use of LEDs producing white light is likely to be OK as well, since these diodes are essentially blue LEDs doped with phosphors that fluoresce longer wavelengths. However, the light intensity of the light produced by even a single blue LED has the potential to be brighter than natural moonlight measured here in Hawaii. Light penetration in aquaria, with their usually shallow (and hopefully clear!) waters, should not be an issue, so using LEDs with a maximum wavelength of 450 or 460nm may actually be an advantage due to their lower output at 480nm.

Since most PAR meters' minimum respond is '1', these units are useless in determining proper placement of a light source in order to mimic natural moonlight intensity. On the other hand, a lux meter can measure moonlight at its maximum intensity although the reading will be ~1. Hence, placement of the LED for providing proper intensity will likely have to be estimated visually. At present, the effects of over-illumination of a reef aquarium at night are unknown but it is possible that it might affect fish or invertebrate spawning behavior.

A number of controllers with abilities to simulate lunar phase are on the market. In absence of one, a handy hobbyist can make a manually-controller lunar simulator with a low wattage incandescent lamp and a rheostat.

Testing Equipment

Spectral characteristics of the moon and LED were measured with an Ocean Optics USB2000 spectrometer and SpectraSuite software. Data were downloaded to an Excel worksheet for post-processing. Moon intensities were recorded by a Li-Cor 1400 quantum meter/datalogger and cosine-corrected quantum sensor.

Acknowledgement

Thanks to my brother David for supplying the photograph of the moon.

Questions? Comments? Please post below or contact me at RiddleLabs@aol.com.

References

1. Anctil, M., D. Hayward, D. Miller, and E. Ball, 2007. Sequence and expression of four coral G protein-coupled receptors distinct from all classifiable members of the rhodopsin family. Gene, 392(12): 14-21.
2. Brady, A., K. Snyder and P. Vize, 2011. Circadian cycles of gene expression in the coral, Acropora millepora. PLoSOne Online.
3. Gorbunov, M., Z. Kolber, M. Lesser, and P. Falkowski, 2002. Photoreceptors in the cnidarian hosts allow symbiotic corals to sense blue moonlight. Limnol. Oceanogr., 47(1), 2002, 309-315.
4. Hunt, R., 1987. Measuring Colour. Fountain Press, Kingston-upon-Thames, England. 344 pp.
5. Hunter, C., 1988. Environmental cues controlling spawning in two Hawaiian corals Montipora verrucosa and M. dilatata. Proc. 6^th Int. Coral Reef Symp., Australia. 2:727-732.
6. Jerlov, N., 1976. Marine Optics. Elsevier Oceanography Series, Elsevier Sci. Publ. Co., New York. 231 pp.
7. Jokiel, P., 1985. Lunar periodicity of planula release in the reef coral Pocillopora damicornis in relation to various environmental factors. Proc. 5^th Int. Coral Reef Congress, Tahiti. 4: 307-312.
8. Levy, O., L. Appelbaum, W. Leggat, Y. Gothlif, D. Hayward, D. Miller, O. Hoegh-Guldberg, 2007. Light-responsive cryptochromes from a simple multicellular animal, the coral Acropora millepora. Science, 318 (5849):467-470.
9. Levy, O., Z. Dubinsky, and Y. Achituv, 2003. Photobehavior of stony corals: Responses to light spectra and intensity. J. Exp. Biol., 206: 4041-4049.
10. Olive, P., 1995. Annual breeding cycles in marine invertebrates and environmental temperature: Probing the proximate and ultimate causes of reproductive synchrony. J. Therm. Biol., 20(1, 2): 79-90.
11. Pressley, P., 1980. Lunar periodicity of the yellowtail damselfish, Microspathodon chrysurus. Environ. Biol. Fishes, 5:155-159.
12. akemura, A., E. Susilo, M. Rahman and M. Morita, 2004. Perception and possible utilization of moonlight intensity for reproductive activities in a lunar-synchronized spawner, the golden rabbitfish. J. Exp. Zoology, Part A: Comp. Exp. Biol., 301A, 10: 844-851.
13. Vize, P., J. Hilton, A. Brady and S. Davies, 2008. Light sensing and the coordination of coral broadcast spawning behavior. Proc. 11^th Int. Coral Reef Symp., Ft. Lauderdale, Florida.

With the help of my colleague David Flanigan, an organic chemistry professor and fellow reef aquarist, I tested the effectiveness of some reflectors used with T-5 fluorescent bulbs in aquarium lighting fixtures. We knew that any sort of reflector in a fixture would help send more light downward into a tank, but we wanted to see some hard data, and wanted to compare a couple of different types of reflectors in the process. So, we set up a test tank, got a light meter and a couple of fixtures, and got to work.

To start, we cut up and marked some eggcrate, attached it to a PVC frame we built (along with uprights of different lengths that could be switched out to take readings at different depths), and got a light meter. We went with the Apogee Instruments Quantum Meter with a cabled sensor, after reading Riddle (2005 & 2008) and talking to lighting expert Sanjay Joshi. This meter measures PAR (Photosynthetically Active Radiation), the important part of the spectrum for organisms that use light, which is also called PPFD (Photosynthetic Photon Flux Denisty). It does this, and then reports intensity in units called micro-Einsteins per square meter per second (µE·m²·sec) or micro-Mol per square meter per second (µMol·m²·sec). Riddle (2008) covers this in more detail, so give it a read if you like.

There are numerous pre-fabricated T-5 fixtures available, and all that I've seen have some sort of reflector included. However, some fixtures have a single reflector that's typically a flat or curved sheet of polished aluminum mounted above all the bulbs in the fixture, while many others have a single, smaller aluminum reflector for each individual bulb. These tend to wrap around half of the bulb and have some number of bends/folds in the aluminum. So, we got one of each type of fixture and tested both. During our tests, we made some other discoveries, quite on accident, and I want to go over a couple of these first, though.

The Background Effect

While some aquarists might leave the back of their tank alone, or may cover it with a sheet of colored plastic, it's common practice to tape up the sides and top of a new tank and spray paint the back of it blue or black. However, one of the accidental discoveries we made was that this can significantly reduce the amount of light that is reflected into a tank.

Our test tank was a 95 gallon tank with dimensions of 24" high x 18" wide x 48" long, as this is a popular footprint, and we did much of our testing with the tank full of water after we found that this can also make a significant difference in readings. The tank was also painted light blue on the backside.

When we started testing, we assumed that light readings would always be lower at the front of the tank and higher at the back. The reasoning was that some of the light from the bulbs should be reflected off the front pane of glass back into the tank and off the rear pane of glass into the tank - but that more light would "escape" through the clear front pane, while more would be reflected back in from the painted back pane. However, were wrong, as the readings at the front of the tank, without exception, were higher instead of lower than those at the back of the tank.

To develop an understanding of why this happened, look at the lighting "footprint" below of our TX5 48" fixture that houses five 48" T-5 bulbs, which was generously donated by Aquactinics. The units are PAR (as µMol·m²·sec) measured in the tank with the sensor at 10" water depth, and note that the front of the tank is at the bottom of the figure. Average PAR at the front of the tank was calculated by adding the 11 readings taken at approximately 1" from the front pane of glass during each test and dividing that sum by the number of readings taken (11).

Notice that the light intensity was lower at the back of the tank where the average was 167 µMol·m²·sec (top of the footprint), and higher at the front where the average was 234 µMol·m²·sec (bottom of the footprint). We found that the same thing happened when we later tested our Nova Extreme fixture that houses four 48" T-5 bulbs, our Orbit fixture that houses four 21" PowerCompact bulbs, and even our Outer Orbit fixture that houses four 48" T-5 bulbs and two 150w DE metal halide bulbs (all of which were generously donated by Current USA). For some reason the painted blue background, without exception, made the back of the tank darker than the front.

It occurred to us that we could take a look at the effect a colored plastic background would have on readings. So, we tightly taped a blue plastic background to the front of the tank to see if the readings would then equal those at the back. The background material we had was about the same color blue as the paint on the back of the tank, so we thought that's what would happen. Wrong again. Let's look at the new footprint, again with the TX5 fixture and everything else the same except for the addition of the plastic sheet.

Well, it looks the same. The readings were essentially the same as before, being ever so slightly higher at the front of the tank. Apparently it was something about the paint itself, rather having something blue on the front/back of the tank. So, just for the fun of it we tried a black plastic background. It didn't really change the readings, either. Thus, it seemed that the color of the plastic sheer didn't matter. The front was still brighter than the back.

Then Dave had a great idea. Next, we tried the blue plastic background again, but this time we wetted the glass on the front of the tank, stuck the plastic to it and then pushed all the air bubbles out from underneath it. Basically our simulated painted background looked just like the real painted background, and was stuck onto the pane itself with no air in between the plastic and the glass. This time we got something totally different, as you can see on the new footprint.

Oddly enough, the readings at the front mirrored those of the back of the tank. Note that the average PAR at the front of the tank is approximately 30% lower than it was when we started, and is essentially identical to the readings along the back (an average of 166.6 µMol·m²·sec for the back vs. 166.9 µMol·m²·sec for the front)!

Okay, so we did one more. Next, we wetted the front of the tank and did the same thing with the black plastic background. The readings dropped even lower, as the average at the front was 155 µMol·m²·sec. So, the front of the tank, with its simulated painted black background, was noticeably darker than the back of the tank with its painted blue background. In fact, the average PAR was down approximately 34%.

Again, this was not what we expected at all. So, we tracked down physics professor Brain Lane, looking for a possible explanation. As he explained, in simple terms, when light leaves its source and hits the panes of glass in the tank, some of that light escapes through the glass, but some is reflected off the inner surface of the glass and heads back into the tank. As strange as it might sound, some of the light also reflects off the inner "surface" of the outer side of the glass pane, too (see the figure below). However, apparently having something "sealed" against the glass, such as blue paint or a wetted blue plastic background stops some of the light from reflecting off the inner surface of the outer side of the glass pane. If anything else was going on, taping the dry plastic background on the tank would have the same effect - but it didn't.

Yes, that sounds odd, but you can easily see some of the weird reflections created when mixing glass, air, and water. Have you ever noticed that if you look right through the front of the tank it looks clear, but if you look through the end of your tank the front pane of glass looks like a mirror? Take a look now if you've never noticed this before. Of course, this doesn't happen if there's no water in the tank, as you can see right through the front pane, even when looking at it through the end of the tank.

Anyway, at this point I want to make some basic recommendations related to the topic. 1) If you have a wall of live rock from the bottom almost to the top of your tank, then don't worry about the background too much. Most of the reflection takes place several inches from the top of the tank. 2) If you have considerable areas of glass exposed at the back of the tank, unobstructed by rocks, use a taped on plastic background instead of paint. Or, try putting your tank close to a wall and just paint the wall behind it blue/black. Again, this can result in the back of the tank being as much as 30% brighter than if it was painted. 3) Always keep your glass clean to promote better reflection regardless of backgrounds, which includes scraping away coralline algae. 4) Don't paint the front of your tank :)

The Temperature Effect

In addition to the background effect, we also noticed another pattern in the numbers that persisted regardless of the type of fixture. The readings were always lower at one end of any given fixture than at the other end, and if you scroll back up and look at the footprints above, you'll see this. The readings were always a little higher on the left end of the TX5 fixture, and we found that this caused by a difference in bulb temperature from one end to the other.

I'll go into more detail on this in a future article, but for now it's enough to point out that the 3" exhaust fan in the fixture was on the right end and it drew relatively cool air from the room into the left end. As the air passed over the bulbs it became increasingly hotter, meaning the bulbs were slightly cooler at the left end of the fixture. Every bulb has an optimal operating temperature, and in this case the bulbs' output fell off a little at the right end of the fixture due to the increase in temperature.

While the end to end differences weren't drastic by any means, they were consistently there. It's unlikely that anyone will be cutting holes in a pre-fabricated fixture and/or upgrading the included fans, but if you decide to install a lighting retro-fit kit into a canopy, be sure to use an appropriately-sized fan(s) for the job and give some thought to placing it/them in the top-center of the canopy with vents in both ends. Putting the fan in the top-center and vents in the ends would decrease the distance that room-temperature air travels over the bulbs, and would keep both ends of the bulbs at approximately the same temperature.

Test Results for a Fixture with a Single Reflector

Okay, let's get on to how we tested some T-5 bulbs with a single sheet-type reflector that has a single fold down each edge, and what we found. To start, we grabbed our Nova Extreme fixture that houses four 48" T-5 bulbs and includes a single polished aluminum sheet mounted above bulbs. Then, we covered the entire reflector with black electrical tape. We put the bulbs in, set the fixture up over our testing rack, and fired it up. One little thing to note here is that we waited about half an hour to start taking readings, as we found that it takes a while for systems to warm up and the light output to stabilize. Again, output changes depending on bulb temperature.

After everything was ready, we took a series of readings to measure PAR using our meter. Readings were taken at fifteen positions under the fixture, five from end to end and three across (see the grid on the figures below). Note that the bottom of the fixture was approximately 5.25" inches from the top of the light meter's sensor.

After finishing that up, we pulled out the black tape, got the fixture warmed up again, and took the same series of readings. This let us make a direct comparison between the light that would be going down into a tank with and without the reflector.

With the reflector blacked-out the highest PAR reading we got was 191 µMol·m²·sec. We also found that the average PAR was 155 µMol·m²·sec, which was calculated by adding all the readings together and dividing the sum by 15. With the tape pulled off the reflector the highest PAR reading was 435 µMol·m²·sec, and the average PAR was 342 µMol·m²·sec. That's quite a difference to say the least, as the average PAR went from 155 to 342 µMol·m²·sec! So, it should be quite clear that the use of a sheet-type reflector can make a heck of a difference in the amount of light going from a T-5 bulb to the critters in your tank.

Test Results for a Fixture with Individual Reflectors

Next, we tested our TX5 48" fixture that houses five 48" T-5 bulbs with individual reflectors for each bulb. They're the type that has numerous folds, and have a little ridge that runs right down the middle of the reflector, too. This little ridge is supposed to angle away the light going straight up from the bulb, rather than reflecting it straight back down into the bulb. Again, these reflectors wrap around each bulb to some degree, and we expected them to be even better than the single sheet-type reflector. Note that due to the width of the fixture we decided to use only three bulbs in it, so the readings we got were lower than those presented above. This doesn't really matter though, as we were looking for the change in readings with and without reflectors rather than the total output of a given fixture.

Again, we covered each of the reflectors with black electrical tape, put the bulbs in afterwards, set the fixture up over our testing rack, and warmed it up. We took a series of readings in the same manner, and then pulled out the black tape, got the fixture warmed up again, and took the same series of readings once again.

With the reflectors blacked-out the highest PAR reading was 128 µMol·m²·sec, and the average PAR was 101 µMol·m²·sec, which again was calculated by adding all the readings together and dividing the sum by 15. With the tape removed the highest PAR reading was 451 µMol·m²·sec, and the average PAR was 304 µMol·m²·sec. So, we were right to think these would send even more light downwards, as the average PAR went from 101 to 304 µMol·m²·sec! Thus, again, it should be obvious that the use of well-designed reflectors, individual-types in this case, can make a huge difference in the amount of light going from a T-5 bulb down into a tank.

Other Bulbs

So, what about V.H.O. bulbs? Do reflectors make as big a difference? Well, all of the V.H.O. bulbs I've ever used had an internal reflector. I assume that's because they have a larger diameter making it easier to add some sort of coating to half of the inside of the bulb to send all the light in one direction. However, we didn't do any sorts of tests on V.H.O.s and I've never broken one open to see what's in there, so I'm not positive about that. Regardless, I don't know of anyone that makes individual reflectors for V.H.O. bulbs. Maybe we'll try a sheet-type reflector with some in the future though, just to see if there's any difference. Likewise, the bulbs used in the L.E.D. fixtures I've seen always come mounted in little individual reflectors, so we didn't test any L.E.D.s without reflectors, either.

Metal halide bulbs and the reflectors made for them come in a range of shapes and sizes and finishes, but there's already a good bit of information about these available. Sanjay Joshi has looked at many of them and written up the results in a series of articles (see references below), but what I'll tell you here is that the right reflector can make a huge difference, and the wrong one won't help much. So, if you're thinking about retro-fitting some into a canopy, I recommend you do some homework on bulb/reflector combinations.

Bottom Line

It is imperative that you use reflectors with T-5 bulbs, and individual reflectors do a better job of sending light into a tank than a single reflector. If for some reason you decided to add some T-5s to a canopy yourself, the data show that you'd need three bulbs without reflectors to send the same amount of light into the tank as one bulb with a quality individual reflector! Also, don't paint the back of your tank, and make sure that your bulbs are adequately cooled for optimal performance.

References / Sources for More Information

1. Joshi, S. and Marks, T. 2003. Analyzing Reflectors: Part I - Mogul Reflectors. Advanced Aquarist's Online Magazine: 2(3).
2. Joshi, S. and Marks, T. 2003. Analyzing Reflectors: Part II - Double Ended Lamp Reflectors. Advanced Aquarist's Online Magazine: 2(7).
3. Joshi, S. and Marks, T. 2004. Analyzing Reflectors: Part III. Advanced Aquarist's Online Magazine: 3(3).
4. Joshi, S. and Marks, T. 2004. Analyzing Reflectors: 400w DE Reflectors. Advanced Aquarist's Online Magazine: 3(12).
5. Joshi, S. and Marks, T. 2006. Analyzing Reflectors: Part V. Advanced Aquarist's Online Magazine: 5(2).
6. Joshi, S. 2006. Facts of Light Part I: What is Light? Reefkeeping: 5(1).
7. Joshi, S. 2006. Facts of Light Part II: Photons. Reefkeeping: 5(2).
8. Joshi, S. 2006. Facts of Light Part III: Making Sense of Light Measures. Reefkeeping: 5(3).
9. Riddle, D. 2005. Product Review: A Comparison of Two Quantum Meters - Li-Cor v. Apogee. Advanced Aquarist's Online Magazine: 4(7).
10. Riddle, D. 2008. Product Review: Lighting for Reef Aquaria: Tips on Taking Light Measurements. Advanced Aquarist's Online Magazine: 7(2).

H2O systems introduced the Waveline DC pumps and RLSS protein skimmers in 2012.  These products are just now coming to market, and Advanced Aquarist has the first review of the new RLSS line.

The Design

The RLSS R10-U is a conventional high-end in-sump needle-wheel design but with an unconventional pump.   A single, submersed Waveline DC-5000 pump performs both air fractionation and water delivery for the skimmer.  Unlike the single speed AC pumps employed by nearly every other skimmer, the Waveline is a speed-controllable direct current pump.  Users can select between six preset RPMs via the included DC pump controller to tune their skimmer's performance.  Six green LEDs indicate the speed.  Users can also engage a 10 minute feed/service shutoff timer;  The pump restarts automatically after 10 minutes or restarts immediately by pressing the timer button for a second time.  The Waveline DC-5000 is a soft-start pump, meaning the impeller will gradually ramp up to full speed on start-up.

H2O Systems includes an air silencer, custom venturi intake, and all the silicone tubing required for operation.  The entire skimmer system (including the Waveline pump) is shipped in a single box.  Some assembly is required, and H2O Systems will soon provide instructions on their website.  Unboxing and assembly took us less than 10 minutes, and no tools were required.

The R10-U measures 10" diameter at the base of the reaction chamber and collection cup (hence the R10 model number).  The entire skimmer (sans the grey PVC plumbing) is manufactured from sturdy acrylic. Fit and finish is top notch.  Read more specifications at the end of this review.

RLSS skimmer users can remove the entire bottom plate (above, left), which is held to the main skimmer body with four plastic thumbscrews.  The bubble plate diffuser is also removable, allowing unobstructed access inside the skimmer body.  Pictured (above, right) is the underside of RLSS' bubble plate diffuser.

The custom RLSS needle-wheel is a generous 2" diameter and spun on an impressively large diameter but short ceramic shaft, reducing potential for imbalances that can generate both noise/vibration as well as excessive wear.  All friction points are ceramic to ceramic, including the bushings (no rubber whatsoever).  This is as robust a needle-wheel assembly as I've seen.

The needle-wheel features dual diameter pins and perforations on the back plate.  H2O Systems claims the stepped pins create finer bubbles and the perforations help reduce heat buildup at the motor.

As an energy-efficient DC pump, the Waveline runs very cool.  In theory, this should also improve reliability and reduce calcium buildup.

The RLSS collection cup is connected to the skimmer body via a slip joint fitted with an o-ring. The connection is watertight and solid.  In fact, if I was to levy my first critical comment, it's that the fitting was too tight.  Removing the collection cup proved awkward.  In theory, a slip fitting should be easier to remove than a screw-on or union collection cup, but I found this was not the case with the review unit.  But I'm nitpicking.

Performance

Let's start with the skimmer's noise level.  The RLSS R10-U is one quiet skimmer, on par with the best Askoll-based (e.g. Red Dragon) protein skimmers such as Bubble Kings.  The Waveline pump generates virtually no noise or vibrations; Whatever vibration that exists is absorbed by the silicone and rubber feet on the skimmer and pump respectively.  The silicone tubing also prevents transference of vibration from pump to skimmer.  The only audible noise comes from the air bubbles and a very low level rotor hum.

How does the R10-U skim?  To find out, I seeded the 20 gallon test reservoir with one cup of tea-colored skimmate (produced with another protein skimmer).  The RLSS R10-U developed a thick head of stable foam nearly instantaneously.  Since there are no standard metrics to quantify skimming performance, I'll let the photos and video speak for themselves.

The noise you hear in the video is the bubbles popping with the lid removed.

The Waveline pump generates a wall of fine bubbles with virtually no microbubbles returned back to the sump, evidenced by the photo above. I found the RLSS R10-U requires 8 inches of water to operate effectively.  Anything less than 7 inches and the pump (at full speed)  will suck air from the water's surface.

Despite the curved cone design and bubble diffuser plate, the internal water column was more turbulent than some of its competitors.  This did not appear to hinder the skimmer's performance as the photos/video show. Unfortunately there is no way to modify the water to air ratio to reduce turbulence; Reducing the pump's speed results in a linear reduction of both water and air.  Again, the skimmer is  clearly capable of producing very thick and stable foam, so the turbulence "problem" may be academic.  And in all fairness, the skimmer may require more time to break in; I spent one week with the review unit before putting the skimmer through its paces.

Conclusion

At $799.99, the RLSS R10-U is not a cheap protein skimmer, but it represents a terrific value compared to its competitors (some costing more than twice the R10-U).  We know this time-tested skimmer body (based on the JNS design) works well, but the heart of any needle-wheel protein skimmer is its pump.  The Waveline DC pump proves it is an effective protein skimmer pump capable of producing ample fine bubbles with minimal noise, heat, and electrical consumption.

Specifications & Pricing

• 10" diameter in-sump protein skimmer
• 18 x 18 x 21.5" (455 x 455 x 550mm)
• 1 x Waveline DC-5000 pump (40 watts)
• Air draw: 900-1800lph
• Rated for 396-660 gallons (1500-2500 liters)
• $799.99 USD

The manufacturer provided this product to Advanced Aquarist for review.

The wavelength of visible light is between 400-700nm. Incidentally, these also happen to be the majority of wavelengths of light that are relevant to photosynthesis. The combined effect of the complete range of radiation between 400-700nm appears as white light to the human eye. Radiation with a wavelength of 400 nm generates a response in the human eye that makes it perceived as violet, while radiation with a wavelength of 700nm appears red. The different colors of the rainbow (ROYGBV - red, orange, yellow, green, blue and violet) are arranged in descending order of their wavelength. Roughly, we can break down the various colors into wavelength bands as follows:

• Violet - 400 to 440nm
• Blue - 440 to 490nm
• Green - 490 to 540nm
• Yellow - 540 to 590nm
• Orange - 600 to 650nm
• Red - 650 to 700nm

Radiation below 400 nm wavelength is called ultraviolet (UV) radiation, and is typically divided into three segments: UV-A (400-315nm), UV-B (315-280nm) and UV-C (280-100nm). UV radiation is not visible to the human eye, but it can have a damaging impact on humans (as well as corals). The UV-A segment, the most common in sunlight, overlaps slightly with the shortest wavelengths in the visible portion of the spectrum. UV-B is effectively the most destructive UV radiation from the sun, because it penetrates the atmosphere and can injure biological tissues. UV-C radiation from the sun would cause even more injury, but it is absorbed by the atmosphere, so it almost never reaches the Earth's surface.

Infrared (IR) radiation has slightly longer wavelengths than visible light. The IR region of the electromagnetic spectrum is also divided into three segments: IR-A (780-1400 nm), IR-B (1400-3000 nm) and IR-C (3000-10600 nm). Infrared radiation is thermal and is felt as heat.

A typical spectral distribution of a light source is measured using an instrument called a spectroradiometer. A spectroradiometer simply is an instrument that has a sensor and associated hardware and software to determine the distribution of energy (measured as power density in Watts/m²) at different wavelengths of the electromagnetic spectrum. The power density at different wavelengths is also called the spectral irradiance. The data is usually displayed as a graph with the wavelength on the X-axis and the spectral irradiance on the Y-axis, and is called the Spectral Power Distribution (SPD) plot. One such SPD plot is shown in Figure 1 below. This is the most important piece of information about a light source, and all relevant light measures can be mathematically derived from it. A point of note here - since the measurement is in terms of watts/m², changing the distance of the light source to the sensor will result in a change in the absolute measured values. Hence for comparison purposes, either the measurements must be made at the same distance or the data scaled and normalized.

The spectral distribution of light from the Metal Halide lamps has been characterized extensively in earlier research ( see http://www.manhattanreefs.com/lighting for a catalog of spectral output of various metal halide lamps). However, little is known about the spectral characteristics of the LEDs currently available to the hobby and how they compare to the spectral characteristics of the metal halide and other light sources that have been used successfully in the past to maintain reef aquariums. The spectral characteristics of light impact both the coral and photosynthetic organisms and the visual aesthetics of the aquarium.

Most of the new LED fixtures for reef lighting are configured with a mix of blue and white LEDs, or more recently with 4 or more different colored LEDs. The resulting light is a blend of the light output of the various LED colors. The light intensity and spectrum is typically a simple additive effect of the individual spectral output of the various LEDs.

Methods and Approach

For the purpose of this study, several popular LED fixtures (Table 1) were analyzed for their spectral distribution. The spectral distributions were measured using the Licor LI-1800 spectroradiometer. The spectral data was collected from the various LEDs and normalized such that integrated light output (spectral irradiance) between the wavelengths of 400-700 nm was 100 Watts/m². Data was collected at full power output for the individual channels of light control (eg. Blue, white) along with data with ALL LEDs on at full power. The data was normalized so that the full output was at 100 Watts/m² over the wavelength range 400-700 nm. The various LED color outputs were then scaled by the same scale factor to allow of determination of the contribution of the various LEDs to the full output. The results are plotted as a SPD plot. Additionally, the spectrum is compared to two popular metal halide lamps - 400W Radium driven by a HQI ballast and a 400W Ushio 14000K driven by an Icecap Electronic ballast. The Radium 400W is a popular bulb among reef aquarists who prefer a "blue" look to the tank, and the 14000K Ushio is the bulb that I currently use on my tank and is a preferred choice for those who prefer a whiter look to the tank. Based on vast amounts of reported success with these lamps, these 2 were chosen as a reference to compare the light spectrum of the various LED fixtures.

Table 1: LED Fixtures evaluated for Spectral Output

Fixtures
Radion X30
Orphek PR-156
Ecoray 112
Mvava-2
Aquaillumination SOL White
Aquaillumination SOL Blue
Aquaillumination SOL Warm White

Radion XR30W

The Ecotech Radion is one of the few LEDs that offers multiple color LEDs, with 2 types of LED blue, white, green and red leds. A total of 8 Cree XP-G Cool White LEDs run at 5W each, 8 Cree XP-E Blue LEDs run at 3W each, 10 Cree XP-E Royal Blue LEDs run at 3W each, 4 Cree XP-E Green LEDs run at 3W each and 4 Osram Oslon SSL Hyper Red LEDs run at 3W each. There are 4 separate channels of control that allow user to customize the light output by adjusting the output of the various channels independently via software program.

The contribution of each of the individual LEDs at full power to the overall resultant spectrum is seen in the figure 2a below. As seen from the figure the final resultant spectrum in a sum of the output of the different spectrums. This is one of the few LEDs with green and red LEDs, in an effort to provide a wider coverage of the light spectrum. The addition of the red leds help improve the color rendition especially for the red/pink corals as well as fish. Also, Chlorophyll in corals has an absorption band in the red region, hence it is speculated that the addition of red will enhance photosynthesis. Figure 2b shows how this compares to the Metal Halide lamps. It is interesting to note that the amount of Red spectrum is quite comparable to that of Radium.

Orphek PR-156

The Orphek array PR-156 is one of the newer models that includes 4 UV LEDs, in addition to the blue and white LEDs. A total of 60 LEDs running at around 2W each make up the complete array. The UV LEDs cannot be individually controlled, hence their output is combined with the main output with all LEDs turned ON. As seen in the figure 3a, the UV LEDs show in the spectral plot between 350 and 400 nm. The amount of UV is still less than what is output by the metal halide lamps as seen in Figure 3b. The Orphek PR 156 allows the moon lights to be controlled separately.

Ecoray 112

Similar to the Ecoray 60 in design, this is the larger version with 112 LEDs - 56 White High Power 1 Watt LED, (color temperature 12000K - 160000K) and 56 Blue Actinic High Power 1 Watt LED (Wave Length 450-460 nm) arranged in a 8X14 grid. The white and blue LEDs can be controlled separately, only in 2 states ON or OFF. The spectral output for the different channels and all LEDs ON is shown in figure 4a along with the comparison to metal halide in figure 4b.

MVAVA-II

MVAVA II LED array (http://www.mvava.com/index.html) comprised 56 1W Blue LED and 8 10W multichip White LEDs, in a ON/OFF control configuration. Figure 5a shows the output of the individual channels and figure 5b shows how it compares to metal halide lamps.

Aquaillumination - SOL White

Aqua Illumination SOL White comprised 24 LEDs in the ratio of 2 Whites: 1 Blue. 16 CREE XPG White and 8 CREE XPE Blue, with custom designed light collimators were used in each module. A single 12" module was tested. These LEDs come standard with a controller that allows infinite control of the blue and white channels. Figure 6a shows the spectral output of the individual channels at full output and figure 6b shows the comparison to metal halides.

Aquaillumination - SOL BLUE

The SOL Blue is similar in construction to the SOL White, with the primary difference being the ratio of blue to white LEDs. 8 Blue and 8 Royal Blue LEDs comprise the blue channel and 8 white LEDs comprise the white channel each of which can be controlled separately. (Note that these were tested before updating the controller and hence the blue and royal blue could not be controlled separately). Figure 7a shows the output of the different channels blue and white, and figure 7b shows the comparison with metal halide lamps.

AI Nano Sol (with warm white)

The fixture includes is a miniature version of the larger SOL White and SOL blue. With (2) Warm White XM-Ls, (4) Blue Cree XP-Es and (4) Royal Blue Cree XP'Es mounted in a pair of LED clusters. The controllers provides 3 channels of control one for each color allowing each to be controlled from 0-100% output. Figure 8a shows the light output of the various channels and figure 8b compares it to the metal halide spectrum.

Discussion

As seen from the data, there are significant spectral differences between the LED spectrum and those of the most popular MH lamps. The LEDs tend to have more output in the blue regions 400-500 nm range, while lacking in the warmer regions of the spectrum. This could explain why the aquariums tend to have a "flat" look when lit by LEDs. Lack of the red spectrum results in corals and fish with red color to look lack lustre. Lack of a broader spectrum and missing quantities of output at wavelengths to promote a more full spectrum is often a concern cited with LEDs, and it is obvious when comparing the spectrums to metal halides. As seen from the newer generation of LEDs there is an attempted to address this by providing more choice of colors (and channels of control) to allow tweaking of individual channels to enable users to fine tune the look of the aquariums and provide the ability to have one light fixture with the potential to satisfy a wide range of users.

There are some difference between the spectral output of the LED fixtures, especially outside the blue spectrum. These differences seen in Figure 9, are primarily due to the differences in the white LEDs being used and the quantity of white light. The figure below shows how the different LED fixture compare against each other and the differences between the spectral output.

These spectral difference will impact the visual look of the aquarium as well have some impact on the colors that develop in the corals. It should be noted that these spectral plots are measured with all lights at 100%, while in practice some users may dim certain colors to create a look that suits them and their perception of how a tank should look. What is obvious, from looking at the individual graphs is that the resulting light spectrum will be a direct addition of the spectral output of the various component lamps. In this regard the LEDs definitely provide a significant advantage over the traditional one bulb one look approach of metal halide lighting. The data presented here should be viewed in conjunction with the distributed data presented in my earlier articles provided in the references.

References

1. S. Joshi, Quantitative Comparison of Lighting Technologies: Metal Halide, T5 Fluorescent and LED, Advanced Aquarist, Vol. IX, Feb. 2010
2. S. Joshi, LED Lighting Tests: Aquaillumination, Blue Moon, Eco-Lamp KR-91, Ecoxotic Panorama, Advanced Aquarist, Vol. IX, May 2010.
3. S. Joshi, LED Lighting Tests: Ecoray, Reef Fanatic, and MaxSpect, Advanced Aquarist, Vol. X, Aug. 2011.
4. S. Joshi, LED Lighting Tests: Radion, Orphek, Mvava, Ecoray and Ecoxotic, Advanced Aquarist, Vol. X1, Jan. 2012.

LEDs are becoming more prevalent in the hobby. New LED fixtures continue to be introduced into the hobby. Continuing in the same vein as my previous LED lighting tests, this article presents data on light intensity and spread for several new LED fixtures.

The following LED lighting fixtures reviewed in this article:

1. EcoTech Radion
2. Orphek PR-156 Array
3. Orphek Pendant DIF 100W
4. Orphek Pendant DIF 50W
5. Ecoray 112
6. Mvava I
7. Mvava II
8. Ecoxotic 100W Cannon

Each of these was tested using the same set up as my previous reflector tests, using a 3'X3' grid with a spacing of 3" in the X,Y direction. The fixtures were centered on this grid, and PAR was measured as PPFD (Photosynthetic Photon Flux Density) in micromoles/m²/sec using a LICOR 1000 data logger and a LI-192SA underwater cosine corrected sensor calibrated for both air and water. The data logger was set to average 5 readings for each data collection point. The data was imported into Microsoft Excel for analysis and the data was plotted to display the light spread and intensity at various distances. 4 plots of the data with 2 plots at each distance were generated showing:

• A 3-D surface plot showing the actual PAR values recorded
• A contour plot viewing the surface from the top showing the distribution

The fixtures were tested for light spread and intensity at 24"and 30", unless otherwise noted. Power draw was measured with a Kill-A-Watt meter.

LED Fixtures Tested

Test Data and Analysis

Ecotech Radion XR30W

The Ecotech Radion offers multiple color LEDs, with 2 types of LED blue, white, green and red leds. A total of 8 Cree XP-G Cool White LEDs run at 5W each, 8 Cree XP-E Blue LEDs run at 3W each, 10 Cree XP-E Royal Blue LEDs run at 3W each, 4 Cree XP-E Green LEDs run at 3W each and 4 Osram Oslon SSL Hyper Red LEDs run at 3W each. There are 4 separate channels of control that allow user to customize the light output by adjusting the output of the various channels independently via software program. Additionally these Radion lights will communicate with any EcoSmart "w" enabled VorTech pumps. Coordinated night mode, storms and other light- and water-synchronized features can be programmed and coordinated by the wireless functionality. As tested the Radion drew 141W of power.

Orphek PR-156 LED Array

The Orphek array PR-156 is one of the newer models that includes 4 UV LEDs, in addition to the blue and white LEDs. A total of 60 LEDs running at around 2W each make up the complete array. As tested the Orphek drew 110W of power. As seen from the light distribution, there are large areas at 24" and 36" where the PPFD values exceed 200. This clearly shows the impact of the optics and will allow these fixtures to be well suited for deeper tanks and mounting higher to get larger spread if desired.

Ecoray 112

Similar to the Ecoray 60 in design, this is the larger version with 112 LEDs - 56 White High Power 1 Watt LED, (color temperature 12000K - 160000K) and 56 Blue Actinic High Power 1 Watt LED (Wave Length 450-460 nm) arranged in a 8X14 grid. As seen from the data, the additional optics clearly focus the light to achieve high PPFD values. This light would be ideally suited for deep tanks (even greater than 30" deep), or allow for higher placement of the light above the tank surface. As tested the Ecoray-112 drews 132W of power.

MVAVA - I Series LED Array

The MVAVA LED array comprised 84 1W LEDs with an equal mixture of white and blue LEDs, housed in a heavy Aluminum case, actively air cooled by fans. As tested the MVAVA-1 drew 132W of power.

MVAVA - II Series LED Array

MVAVA II LED array comprised of 56 1W Blue LED and 8 10W multichip White LEDs, in a similar Aluminum case with actively air cooled by fans. As tested the MVAVA-II drew 172W of power.

Multichip LED Pendants

While the previously discussed LED fixtures were arrays of single LEDs, high power multichip arrays provide yet another option. Multichip arrays provide high wattage LEDs on a single chip by combining several LED multichip emitters in a single package. This eliminates the need for wiring large arrays of LEDs and using individual reflectors. The Orphek pendants and Ecoxotic Cannons are examples of multichip LEDs that are available to the hobbyist.

6a. Orphek DIF 50 (blue+UV) and DIF 100 (20,000K white) Pendant

The Orphek DIF50 (blue+UV) Pendent and DIF 100W (20,000K white) pendants were tested only at 24", due to the length of the pendants and the ability to accommodate them in the light testing setup. As tested the DIF 50 drew 31W and the DIF 100 drew 86W. Discussion with the Orphek representative revealed that this was most likely a adjustment error on the part of the manufacturer and they should be running closer to 50W and 100W respectively. Running at higher output would increase the light output.

6b. Ecoxotic 100W Photon Cannon

The Ecoxotic 100W Photon cannon is another example of the multichip LED. As seen from the data in the figure 9, the light output at 24" is comparable to that of the Orphek DIF 100. As tested the Ecoxotic 100W Cannon drew 93W.

Conclusions

As LED lighting moves further into the mainstream, there a lot of new choices available to the aquarist. Hopefully this data will help the aquarist make an informed choice on what to expect from the individual LED fixtures and how best to utilize them to achieve the desired coverage and light intensity. In my experience a target of approximately 100 micromoles/m²/sec at the bottom of the tank will provide enough of a light gradient to satisfy a wide range of corals. Multiple fixtures will provide regions of overlapping light distributions which provide an additive effect thereby increasing the light intensity and area covered.

Imagine a LED lamp, a giant LED lamp. A 30-watt LED some 2.5 inches (~6.4cm) in diameter and that's what you've got with Blue Moon Aquatic's new P30 LED pendant luminaire. The difference between this product and most other LED luminaires currently on the market is much more than cosmetic. Instead of the more traditional approach, where banks of 3mm LEDs are stuffed into a rectangular housing, Blue Moon Aquatics started off with a clean sheet of paper and designed the P30 from the ground up. The P30 is presently available in two configurations - either with or without an annular 'Saturn ring' consisting of 6 blue LEDs. The unit can be upgraded later with the 'Saturn ring' in just a couple of minutes if desired (the upgrade procedure involves removing a threaded plate and plugging in the blue LEDs. Simple, with no fuss or rewiring).

Specifications

The P30 is designed to be a pendent luminaire and suspended from the ceiling above the aquarium. There are no moving parts, as no cooling fans are involved. Heat is dissipated through a multi-finned cylindrical aluminum heat sink.

Specifications are as follows:

• 2.5" diameter acrylic lens with 30 x 1-watt LED chips
• Power Consumption by 30 LED chips: 30w @ 0.26a @ 119.3v
• Optional 6 1/8" annular ring with 6 x 3-watt blue LEDs
• Power Consumption by 6 blue LEDs: 16-17 watts @ 0.14 amp @ 118.7 v
• Total Power Consumptions (all lights on, with option Saturn ring): 49w @ 0.41a @ 119.1v
• 9' 8" hanging cord (steel)
• Transformer (ballast) has individual on/off switches for blue & white LEDs
• 5' 6" power cord plug to transformer (ballast)
• 10' 6" power cord from transformer (ballast) to luminaire
• Corrosion-resistant aluminum housing

Spectral Qualities

Spectral quality of light illuminating a planted freshwater aquarium or coral reef tank is extremely important since the aquarist wishes to promote photosynthesis. In general, aquatic environments are deficient in warmer wavelengths such as yellow, orange and red. There are studies suggesting too much red in lighting for a reef tank is a cause of bleaching, where corals lose their symbiotic algae (Symbiodinium species). While ratios of red to blue light wavelengths have yet to be determined, we should look for reef lighting that offers minimal red (just enough to satisfy the visual requirements of the viewer) and are skewed towards cooler light such as violet and blue.

Table 1. Light quality of all LEDs in tabular form.

Corrected %
Violet	0.5%
Blue	39.3%
Green-Blue	9.6%
Blue-Green	10.8%
Green	6.4%
Yellow-Green	15.8%
Yellow	4.5%
Orange	8.3%
Red	4.9%

Table 2. Light quality of only blue LEDs in tabular form.

Corrected %
Violet	0.7%
Blue	46.1%
Green-Blue	20.8%
Blue-Green	23.7%
Green	5.7%
Yellow-Green	1.8%
Yellow	0.2%
Orange	0.3%
Red	0.7%

Table 3. Light quality of only white LEDs in tabular form.

Corrected %
Violet	0.5%
Blue	36.2%
Green-Blue	3.5%
Blue-Green	4.3%
Green	6.9%
Yellow-Green	22.8%
Yellow	6.6%
Orange	12.2%
Red	7.1%

Photosynthetically Active Radiation (PAR)

Photosynthetically Active Radiation (PAR) is the portion of visible solar (or artificial) radiation that promotes photosynthesis. It is usually defined as those wavelengths between 400nm (violet) and 700nm (red). It is measured with a PAR or quantum meter and is reported in units called micromol per square meter per second (µmol·m²·sec) but older references may use the unit of microEinsteins per square meter per second (µE·m²·sec). Either way, the PAR meter reports the number of light particles (photons) falling on a surface of a given give over a given time period and is called Photosynthetic Photon Flux Density (PPFD). Sunlight, on a clear day at noon, is about 2,000 µmol·m²·sec but might be as high as 2,500 µmol·m²·sec (depending upon latitude and season).

Although light requirements vary between different plants and algae (including zooxanthellae), a good rule of thumb is to maintain at least 100 µmol·m²·sec. For those using a lux meter, see here for conversion factors for various lamps: www.advancedaquarist.com/2008/2/review

Light intensity falls as distance increases from the source. PAR was measured at various distances in air. Figures 7 through 11 demonstrate results.

Ultraviolet Radiation (UVR)

LEDs usually produce very little radiation unless specifically designed to do so. The LEDs used in the P30 luminaire do not produce any appreciable UVR. See Figure 12.

Many hobbyists mistakenly believe UVR is necessary in a reef tank in order to either promote production of fluorescent coral pigments or to induce fluorescence. UVR is almost always not required and the blue portion of these lamps spectra is sufficient to make corals glow.

How High Above the Aquarium?

The spectral quality of the P30 meets our requirements, and light intensity should be no issue. Placing the luminaire about 10 inches above the water's surface should deliver about 500 µmol·m²·sec. See Figure 13 for further information.

Operating Temperature

Excessive heat is an enemy of the reef aquarium. While warmer water has less ability to hold dissolved oxygen, impacts pH values slightly, generally encourages higher biological activity and others, it is temperature tolerance of zooxanthellae that should most concern the hobbyist.

Figure 14 shows the relative amount of infrared radiation produced by the P30.

The P30 incorporates no cooling fan, and heat transfer is passively accomplished through a multi-vane heat sink. I was interested in recording the temperature of the P30's aluminum housing over a period of time. See Figure 15.

As Figure 15 shows, the warmest part of the luminaire (the top) did not exceed about 125°F indicating this heat sink design is efficient. This temperature was significantly reduced when a small fan was used to aid in heat transfer.

For comparative purposes, operating temperatures of various aquarium lamps are shown in Table 4.

Table 4. Operating Temperatures of Various Aquarium Lamps

	Maximum Observed Operating Temperatures (°F)
P30 LEDs	129
8 watt CFL	131 - 167
60-watt Incandescent	247
Metal Halide Lamps	500 - 600

Ballasts are often overlooked as a potential heat source of aquaria. I scanned the surface of the P30's ballast after an hour of operation and recorded a high temperature of 99.6° F. A reasonable temperature indeed, considering room temperature was ~85° F. However, it is probably a good idea to locate the ballast outside of the aquarium cabinet (if applicable). The generous electrical cord lengths should make this a relatively easy task.

Comments

The light output of the Blue Moon Aquatics P30 is impressive, especially when equipped with the option 6-LED 'Saturn ring'. PAR output by the P30 (with Saturn ring) approach (or in some cases exceed) that produced by many lower wattage metal halide lamps. What seemed impossible to many just a few years ago is now reality - this LED luminaire can complete with metal halides when used over coral reef aquaria of sizes commonly seen in homes. There are obvious benefits - reduced operating costs, low heat production and lamp longevity. An interesting heat sink has negated the need for a cooling fan (all too often the first item to fail in a warm, humid, and sometimes salty) environment. However, the use of a small cooling fan (such as those marketed to blow across the water's surface and aid in evaporation in aquaria) can significantly reduce the operating temperature of the LEDs, or more correctly, the temperature of the aluminum housing. LEDs produce more light at cooler temperatures (at least the lower end of those seen surrounding aquaria housing corals and tropical fish).

Spectral quality will meet the needs of both freshwater and reef hobbyists. My opinion is this: Use the optional Saturn ring along with the P30 for marine fish and reef aquaria. The P30 without the Saturn ring should be fine for freshwater fish and planted tanks.

Since the P30 combined with Saturn ring utilizes a central 'white' light source surrounded by an annular ring of 6 blue lamps (both with optics of different light dispersion angles), the interesting possibility of spectral tuning by altering height of luminaire is possible.

Likes:

• Price - LEDs are now competitive with metal halide and fluorescent lighting systems
• Originality (and functionality) of design
• Light Output (PAR)
• Generous electrical cord lengths

Dislikes:

• Blue and white LEDs cannot be separately controlled by a timer

I have used nothing but LED luminaires for the last few years and have been impressed by the rapid improvements and price reductions. LEDs are here to stay, and I predict will antiquate within a decade other lighting systems used over even the largest of aquaria (yes, I'm speaking of large public aquaria).

Specifically, I've had another Blue Moon Aquatics LED system in operation for over a year and report no problems with it. If that is any indication, I should get long, reliable service from the P30 luminaire.

 

MSRP and Warranty

• Recommended P30 Retail Price: $499 (U.S.), Saturn Ring: $119 (U.S.)
• Warranty: 2-year warranty
• Extended Warranty Available: No

Testing Protocol

Spectral qualities were determined through use of an Ocean Optics USB2000 fiber optic spectrometer. Raw data were exported to an Excel spreadsheet where corrected spectral information was generated with use of a proprietary program written by Dr. Charles Mazel.

Electrical consumption was measured by a Kill-A-Watt meter manufactured by P3 International.

Photosynthetically Active Radiation was determined with a LI-1400 quantum meter made by Li-Cor BioSciences.

Temperatures were measured with a non-contact infrared thermometer.

Contacts

www.bluemoonaquatics.com

Questions? Comments? Please leave them in the Comments section below, or email me at RiddleLabs@aol.com.

The FTC requires us to inform you that the author was given the product gratis for review.

When I first started work in a laboratory, determination of various aqueous constituents was a laborious task, beginning with mixing standards, manually graphing their absorbances, and then making comparisons with samples' absorbance tests results. We manually recorded this information and charted it on graph paper. It was state-of-the-art for the 1970's. We would be (and are) amazed with today's analytical instruments. Compact, battery-operated colorimeters (a type of spectrometer) use conveniently packaged chemicals to quickly determine concentrations of various aqueous substances.

Of particular interest to me in this new world of laboratory instruments are devices used to analyze for alkalinity and phosphorus. Hanna Instruments offers relatively inexpensive colorimeters called 'Checkers' priced at about $50-$60 each (including a small supply of reagents, 2 test tubes, and carrying case). These instruments are small and highly portable. But how accurate are they, and are they worthy of your consideration? This article will attempt to answer these questions.

Hanna Instruments

Hanna Instruments (Woonsocket, Rhode Island, USA) has been in business since 1978, and today offers over 3,000 products to its customers worldwide. Many of their products are of interest to aquarist and Hanna has in fact targeted the aquarium market. For more details, see 'Contact Information' near the close of this article. Hanna imports the Checkers and their reagents from Europe (Romania).

Why Test?

Since you're reading an article about testing for phosphorus and alkalinity, I'll make an assumption you understand the role they play in aquaria. If you'd like to learn more about these, see:

1. Phosphates: http://reefkeeping.com/issues/2006-09/rhf/index.php
2. Alkalinity: http://www.advancedaquarist.com/2002/11/chemistry

Glossary

The following terms are used in this article:

Cuvette

A vessel for holding water, especially a transparent laboratory vessel (such as a test tube)

Colorimeter

A device for determining the concentration of a substance dissolved in liquid by comparing the intensity of its color with that of standard solution(s) of known concentration(s)

mg/L

milligrams per liter, essentially the same thing as ppm

ppm

parts per million

Reagent

A substance for use in a chemical reaction, especially for analysis

Spectrometer

For our purposes, an optical instrument capable of measuring intensity of transmitted light at a specific (but varying) wavelength, especially for determining the concentration of a dissolved substance

Titrant

The liquid reagent used in titrations

Titration

A method for determining the concentration of an aqueous substance by adding a liquid reagent of known concentration and measuring the volume necessary to convert the substance from one form to another

Methods and Materials

First of all, the results shown here are simply comparisons of those gathered by different analytical means. No standards were tested, and I am operating on the assumption that results of Hach's EPA-approved methods and a 'laboratory-grade' spectrometer are most accurate. In addition, only one Hanna instrument each was used in these comparisons.

Water, gathered from a functioning marine fish-only aquarium, was used for the testing.

Samples tested for phosphate were gathered in acid-washed glassware and analyzed within a few hours' time. Initial analyses indicated the phosphate content was at the upper detection limits of both instruments used (a Hach DR2800 spectrometer and the Hanna HI-713 colorimeter). Simple dilution with deionized water brought the phosphate to concentrations spanning the full range of both instruments and to levels realistically found in many reef aquaria. The Hanna and Hach devices both use the ascorbic acid chemistry method for analyses.

Comparing alkalinity results is not as straight-forward. The Hanna device estimates alkalinity through colorimetric analysis. Apparently Hanna has made correlation of chromatic shifts (indicating pH) and the impact of an acidic titrant on alkalinity. While making for a quick and convenient test, there are caveats. First, the amount of alkalinity determines the titration endpoint. In addition, the presence or absence of phosphate and/or silica also affects testing protocol (See Table 1 for titration endpoints).

Table 1. Titration end-point pH Values.

Test Condition		End-Point pH Values
Alkalinity Concentration (as ppm CaCO3):	30	4.9
	150	4.6
	500	4.3
Silicates, Phosphates present or suspected		4.5

For comparative purposes, alkalinity values were determining using the Hanna's colorimetric method and an end-point pH titration method. Hach reagents (sulfuric acid, either 0.160 or 1.600N) were used to titrate a magnetically-stirred sample. A calibrated meter monitored pH.

End-points depended upon alkalinity values shown in Table 1 while Figure 1 shows various endpoints based on alkalinity concentrations. Figure 2 is a photo of equipment used in measuring alkalinity according to EPA guidelines.

With background information out of the way, we can now turn our attention to Hanna's HI-755 and HI-713 devices.

Alkalinity: Hanna Instrument HI-755

Hanna advertises these specifications for their Alkalinity Checker:

Hana Specifications for Alkalinity Checker

Item	Specification
Range:	0 to 300 ppm (mg/L) (some retailer ads incorrectly say 250 ppm)
Resolution:	1 ppm (or mg/L, if you prefer)
Accuracy :	±5 ppm (mg/L) ±5% of reading @ 25°C (77°F)
Battery Type:	One 1.5V AAA (included)
Light Source:	LED @ 610 nm
Light Detector:	Silicon photocell
Environment:	0 to 50°C (32 to 122°F); 95% Relative Humidity maximum, non-condensing
Auto-off:	Yes, after ten minutes of non-use
Dimensions:	81.5 x 61 x 37.5 mm (3.2 x 2.4 x 1.5")
Weight:	64 grams (2.25 oz.) - actually a little heavier (~75 g - yes, I checked!)
	Colorimetric method, using a liquid pH indicator (bromcresol green)

As discussed in detail in the Methods and Materials section, the results from the Hanna Checker were compared to analyses performed by the acid titration method using endpoints dictated by alkalinity concentrations and the presence of phosphates and/or silica. The results are shown in Figure 3.

Next, we'll look at the Hanna Phosphorus Checker. Hanna advertises these specifications:

Phosphorus (Low Range), Hanna Instrument HI-713

Suitable for freshwater, brackish and seawater. Model Tested: HI-713 Phosphorus, Low Range

Hana Specifications for Low Range Phosphorus

Item	Specification
Range:	0.00 - 2.50 ppm (mg/l) as Phosphate (PO43-)
Resolution:	0.01 ppm (mg/l)
Accuracy :	±4 % of reading @ 25°C (77°F)
Battery Type:	One 1.5V AAA (included)
Light Source:	LED @ 610 nm
Light Detector:	Silicon photocell
Environment:	0 to 50°C (32 to 122°F); Relative humidity: 95% maximum, non-condensing
Auto-off:	After two minutes of non-use, and ten seconds after reading
Dimensions:	81.5 x 61 x 37.5 mm (3.2 x 2.4 x 1.5")
Weight:	64 grams (2.25 oz.)
Analytical Chemistry:	Ascorbic Acid Method: Ammonium molybdate and potassium antimonyl tartrate react in an acid medium with ortho-phosphate to form phosphomolybdic acid that is reduced to molybdenum blue by ascorbic acid.
Interferences:	Silicates in excess of 10 mg/l; highly colored water (such as visibly yellow water)

As discussed in detail in the Methods and Materials section, the results from the Hanna Checker were compared to analyses reported by a Hach 2800 spectrometer and ascorbic acid reagent. The results are shown in Figure 4.

Comments and Recommendations

In many cases, results from colorimeters (and other photometric devices such as spectrometers) are superior to visually judging (comparing) colored samples. In fact, Standard method states: Visual comparisons of treated samples in Nessler tubes is not better than 5% (more often 10%) whereas photometric analyses can be reliable to within 3%, depending upon many factors. Naturally, the photometric device can eliminate personal biases of the user as well as accurately and precisely differentiate between small increments of sample absorbance/transmission.

If photometric analyses are potentially superior, the question of device engineering and quality becomes the issue (that is, will an inexpensive device deliver results comparable to an expensive one?). Under the conditions stated in the Methods and Materials section (above), these observations and recommendations are made:

Hanna Alkalinity Checker

These observations apply to the Hanna Checker HI-755 (Note the instrument is marked 'Checker Marine' suggesting it is intended for seawater analyses only):

Likes:

• Easy to use
• Results are generated in seconds
• The procedure is simple - no drip titration is required (just add reagent, shake, and read)
• Does not require any manual conversions (results are expressed as parts per million calcium carbonate)
• Replacement reagent is inexpensive
• Auto-shutoff
• Reagents marked with expiration date
• Small sample size (10 milliliters)
• Spare cuvette included
• Directions and MSDS available online

Dislikes:

• Alkalinity measurements were consistently higher than those generated by the titration/pH end-point method
• Multiple measurements are not possible without zeroing the instrument each time
• No Material Safety Data Sheet included (see below for link)
• Reagent will stain skin and clothing (all procedures using organic dyes carry the same risk)
• Battery replacement requires a small screwdriver and removal of a tiny screw

Recommendation (Alkalinity):

Though my quick comparisons showed the Hanna Alkalinity Checker delivered results consistently higher than those obtained with an EPA-approved method, I am impressed with the speed and ease of measurement. If I were to establish a correction (and comfort) factor to apply to the Hanna Checker's results, this would be my method of choice for establishing alkalinity concentrations.

I recently received a Hach catalog advertising their version of a colorimetric alkalinity test. Hach's chemistry, just as Hanna's, apparently uses bromocresol green sodium salt in the analysis method. It seems this method is becoming widely accepted, if only for estimations (this is not an EPA-accepted procedure).

Recommendation: Yes, with some reservations

Footnote:

• 1 ppm Alkalinity as CaCO₃ = 0.02 milliequivalent per liter (meq/L)
• 1 ppm Alkalinity as CaCO₃ = 0.056 degrees Carbonate Hardness (dKH, or German Hardness)

Hanna Phosphate Checker

These observations apply to the Hanna Checker HI-713 (Low Range Phosphate):

Likes:

• Results compare very favorably with those generated by a much more expensive device
• Much less expensive than a full-blown spectrometer or photometer
• Easy to use and portable
• Results are generated in several minutes (including a 3-minute reaction time)
• The Checker incorporates a timer
• The procedure is simple - Add reagent, shake and bake for several minutes, and read results in parts per million as phosphate
• Replacement reagent is competitively priced
• Auto-shutoff
• Reagents work in fresh, brackish, and saltwater
• Reagents marked with expiration date
• Low Battery, Dead Battery, Under Range, Over Range, Inverted Cuvettes, High Light and Low Light errors are displayed when appropriate
• Small sample size (10 milliliters)
• Spare cuvette included
• Directions (but not MSDS) available online

Dislikes:

• Test results for phosphate are displayed for only 10 seconds after they are reported
• Multiple measurements are not possible without zeroing the instrument each time
• No Material Safety Data Sheet available
• Battery replacement requires a small screwdriver and removal of a tiny screw

Recommendation (Phosphate): Yes!

Footnote: To convert PO₄³ to P, divide by 3.066

Reagent Cost Comparisons

The following approximate prices are for replacement reagents only, and do not include instruments (unless noted), taxes, insurance, or shipping costs.

Phosphate:

• Hanna Phosphate Reagents: $27.99 U.S. per 100 tests
• Hach PhosVer3: $28.19 U.S. per 100 tests (10 milliliter sample)
• Footnote: The Hanna HI-714 phosphate colorimeter can use Hach reagents (ascorbic acid powder pillows).

Alkalinity:

• Hanna Alkalinity: $9.99 U.S. for 25 tests (~40 cents per test)
• Hach: Alkalinity for digital Titrator, $59.17 - includes sulfuric titration cartridges, phenolphthalein and bromcresol green/methyl red reagents. $219 includes reagents and Digital Titrator. To comply with EPA guidelines, a pH meter is also required, and a magnetic stirrer is useful.
• Hach's new colorimetric Total Alkalinity test (25-4,000 mg/l as CaCO₃): 25 tests for $31.45 ($1.26 U.S. per test) using only their spectrometer models DR2800, 3900 and 5000 (Note: These spectrometers begin at about $3,500 U.S.)

Material Safety Data Sheets (MSDS)

The two kits I obtained did not include Material Safety Data Sheets. Here is a link to the Alkalinity reagent: http://www.hannainst.com/sds/SDS_HI%20755S_2010-12-14.pdf I could not find a link to the Low Range Phosphate reagents on Hanna's website at the time of this writing.

Sampling Procedures

"Garbage in; Garbage out" is a saying applicable to results generated when improper sampling procedures are in place. Use reasonable care when gathering samples for analyses. It is recommended that the vials (cuvettes) supplied by Hanna are used when sampling to avoid contamination.

Alkalinity: Analyze immediately or fix sample by refrigerating at 4°C (39.2°F) for up to 24 hours. Bring to room temperature before analysis. If the sample is gathered in a container other than Hanna's cuvette, either clean plastic or glass is OK, and it should be completely filled to avoid prolonged exposure to any air trapped in the bottle. Filter if the sample contains excessive suspended particles.

Phosphate: Analyze immediately. Use the Hanna 10 milliliter cuvette to draw the sample if possible. If not possible, use clean plastic or glass containers - they should be scrupulously clean - preferable acid-washed with 1:1 hydrochloric acid and rinsed with de-ionized water. To fix the sample, exclude particulate matter via filtration and refrigerate at 4°C (or 39.2°F). Maximum holding time is 48 hours.

Treat the cuvettes with respect, and keep them clean and free of scratches. Don't allow the treated samples to remain in the cuvettes any longer than necessary as the chemicals might stain the glass. If the vials do become stained, gently clean them with paper used for sensitive applications (such as that used to clean camera lenses). In extreme cases, a dilute bleach solution may be required to remove the stains. Some hobbyists keep the vials filled with deionized water between uses to prevent spotting within them.

Other Instruments from Hanna

Many of Hanna's other instruments may be of interest to aquarist, including:

• HI-727 Color of Water (0-500 Platinum-Cobalt Units; absorbance @470nm)
• HI-736 Phosphate Ultra-low Range (0-200ppb; Ascorbic Acid Method)
• HI-718 Iodine (0-12.5 mg/l; DPD Method)
• HI-706 Phosphate High Range (0-15mg/l; Ascorbic Acid Method)
• HI-717 Phosphate High Range (0-30mg/l; Ascorbic Acid Method)
• HI-764 Nitrite Ultra-low Range (0-200 ppb)

Contact Information

Hanna Instruments has targeted the aquarium market and has devoted a webpage to hobbyists. See: aquariums@hannainst.com

Specific questions concerning Hanna instruments and aquaculture can be addressed to Jessica Hoagland, Email: jhoagland@hannainst.com

Or write to:

Hanna Instruments, Inc.
584 Park East Drive
Woonsocket, RI 02895

Additional Comments

These products were obtained through normal retail channels, and descriptions, specifications and other information were current at the time of writing.

Questions? Comments? I am best reached at: RiddleLabs@aol.com or sound off in the comments below.

References

1. Holmes-Farley, R., 2006. Phosphate and the reef aquarium. http://reefkeeping.com/issues/2006-09/rhf/index.php
2. Holmes-Farley, R., 2002. Chemistry and the aquarium: Solving calcium and alkalinity problems. http://www.advancedaquarist.com/2002/11/chemistry

 

The last article reported test results on some LED fixtures. This article presents results on lighting output for some more LED fixtures available in the market. Table 1 presents a list of the LED lighting fixtures reviewed in this article. Each of these was tested using the same set up as my previous reflector tests, using a 3'X3' grid with a spacing of 3" in the X,Y direction. The fixtures were centered on this grid, and PAR was measured as PPFD (Photosynthetic Photon Flux Density) in micromoles/m²/sec using a LICOR 1000 data logger and a LI-192SA underwater cosine corrected sensor calibrated for both air and water. The data logger was set to average 5 readings for each data collection point. The data was imported into Microsoft Excel for analysis and the data was plotted to display the light spread and intensity at various distances. 4 plots of the data with 2 plots at each distance were generated showing:

• A 3-D surface plot showing the actual PAR values recorded
• A contour plot viewing the surface from the top showing the distribution

Table 1: LED Lighting Fixtures Tested

LED Fixture	Picture
Reef Fanatic -120W
Ecoray 60W
MaxSpect G2 -160W

The Reef Fanatic 120 LED fixture was tested at 18" and 24", the EcoRay at 18", 24", and 30".

Test Data and Analysis

Reef Fanatic -120W

ReefFanatic's 120W LED Pendant. It has a 1:1 ratio of blue and white LEDs arranged as 3 banks of LEDs. Each bank can be individually shut on/off using the on/off buttons on top of the pendant. A digital timer is integrated with the unit. Since the LED fixture looked very similar to the Blue Moon 90W tested earlier, and the major difference seemed to be in the number of LEDs being used, it was decided to test this at 18" and 24". As tested the fixture drew 130W of power, 1.1Amps current at 120 Volts, with a power factor of 0.99. Cooling of the LEDs is provided by fans built in to the fixture. The distribution of light is shown in figure 1.

Ecoray 60

The Ecoray 60 has 60 1W LEDs arranged in a 6X10 grid, with a equal mix of blue and white LEDs. Unlike the Reef Fanatic LEDs, these LEDs also have integrated optics which help focus the light by reducing the wide spread of the LED light. These were tested at distances of 18", 24" and 30" to assess the distribution of light. As seen from the data, the additional optics clearly focus to light to achieve high PPFD values. This light would be ideally suited for deep tanks (even greater than 30" deep), or allow for higher placement of the light above the tank surface. As tested the Ecoray-60 draws 62W of power, .54Amps of current at 123V, with a power factor of 0.95.

MaxSpect G2 -160W

Unlike the other LEDs, the MaxSpect G2 incorporates a wider range of LEDs with various color temperatures and power. In a 16" x 7.25" x 2.5" high gloss black package, it includes 4 15w 16000K LED, 8 3W 12000k LED, 14 3w Royal Blue LED's (445nm), 4 3w Violet(403nm) and 4 .1w Moonlight LED with 60 degree optics. A 3 Channel Lighting timer is provided for control. As tested the Maxspect-G2 draws 157W of power, 1.33 Amps of current at 121.9V, with a power factor of 0.98

Conclusions

LED lighting for reef tanks is on its way to becoming a reality, and various designs and configurations are making their way into the market. This is a rapidly developing area and unfortunately rapid product changes are not uncommon. On the plus side rapid design changes are benefit to the customer in being able to provide the most current state of the art, while on the negative side making the expensive products obsolete quickly.