Product Review: Analyzing Reflectors: Part V
Since the last set of reflector tests in 2004, I have received five new reflectors for various metal halide lamps. This article presents test results on the fixtures/reflectors available for these lamps. The reflectors were tested using the same setup and methodology as used for the tests on other reflectors, described in . The data is also presented in an identical manner with plots for light dispersion for each reflector at distances of 6", 9" and 12" from the center of the lamp. This article continues in a similar vein as the previous reflector articles and presents the data and analysis of the remaining reflectors in my inventory.
|PFO Lighting New 400W/250W DE Reflector||400W PFO HQI Ballast||HappyReefing 400W DE 10000K|
|PFO Lighting New 400W/250W DE Reflector||250W PFO HQI Ballast||AB 250W DE 10000K|
|Icecap 400W/250W DE Reflector||250W PFO HQI Ballast||AB 250W DE 10000K|
|Sunlight Supply - LumenMax||400W Magnetic Ballast (M59)||USHIO 400W 10000K|
|Icecap 70/150W Pendant||Icecap 150W Ballast||Iwasaki PAR Lamp 6500K, Med base.|
Reflector Data and Analysis
The data plots for each reflector at the distances 6", 9", and 12" are plotted as a surface graph, top view graph, and a % distribution graph to illustrate the intensity and spread at different points on the measuring grid. Table 2 below shows the list of figures associated with each reflector.
|PFO Lighting new 400W/250W DE Reflector - 400W DE Lamp||Figs. 1-3|
|PFO Lighting new 400W/250W DE Reflector - 250W DE Lamp||Figs. 4-6|
|Icecap 400W/250W DE Reflector||Figs. 7-9|
|Sunlight Supply - LumenMax||Figs. 10-12|
|Icecap 70/150W Pendant||Figs. 13-15|
One of the measures of a reflector performance could be its ability to direct light into the aquarium. A reflector's total incident light upon a surface of a given area is representative of the performance of a reflector. It is computed by adding up all the measurements taken at the discrete points within the region. It demonstrates how much light the reflector is able to focus downward when compared to other reflectors with similar operating conditions (same ballast and lamp). While it can be argued that adding all the PPFD values is technically not a valid measure as per the definition of PPFD (since PPFD is defined as microEinstiens/m2/sec), it can be used to provide a metric for reflector performance. Further summing over the data points on a given area can easily be used to compute the average, if so desired. Since the area under consideration is the same for all reflectors, we can just as well use the sum of the PPFD values distributed over this area (169 data points) instead of an average as a performance metric.
Table 3 presents this data for the reflectors in this article. Note that the initial PPFD values of the lamp/ballast combo used to test the reflector influences this data. For example, the PFO DE reflector used a 400W DE lamp on an HQI ballast with a PPFD value of 229 where as the Sunlight Supply Lumenmax used an Ushio 400W lamp on a magnetic ballast with a PPFD of 120.
||Total Incident Light||
|PFO Lighting new 400W/250W DE Reflector - 400W DE Lamp||6"||61861||61756||55161||4226|
|PFO Lighting new 400W/250W DE Reflector - 2500W DE Lamp||6"||36452||36384||32389||2220|
|Icecap 400W/250W DE Reflector||6"||42529||41921||33345||3176|
|Sunlight Supply - LumenMax||6"||46636||46542||28846||1682|
|Icecap 70/150W Pendant||6"||22914||21987||18245||2539|
In addition to knowing how much light is incident on a given area, we could also look at how much loss of light occurs on a given area when moving the lamp and reflector higher. Table 4, presents the % of light lost on a specified area as one moves the lamp/reflector from 6" to 12" above the surface. A higher % loss would indicate that the reflector is creating a larger spread.
|PFO Lighting new 400W/250W DE Reflector - 400W DE Lamp||9.5||18.5||48.7|
|PFO Lighting new 400W/250W DE Reflector - 250W DE Lamp||17.8||26.6||54.6|
|Icecap 400W/250W DE Reflector||7.8||22.5||43.6|
|Sunlight Supply - LumenMax||1.9||12.0||26.3|
|Icecap 70/150W Pendant||10.9||20.9||43.4|
This article is the 5th (and possibly last) in this series and presents the data and a brief analysis some of the new reflectors I received in the past year.
We would like to thank several people whose help made this study possible. They were kind enough to provide us with lamps, reflectors and ballasts for testing: Patrick at PFO Lighting, Andy at Icecap, Dave at Sunlight Supply.
- Joshi, S. and Marks, Timothy. 2003. Analyzing Reflectors: Part I - Mogul Reflectors http://www.advancedaquarist.com/issues/mar2003/feature.htm