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I live in Hong Kong and have been keeping marine aquarium
fish since I was a child. In 1996, I started a 120 gallon (48"x24"x24")
marine fish tank. The aquarium is a standard 4 foot tank with a custom made wooden cabinet
for support. There were neither holes drilled nor overflow included. About 3 years ago, I
went to visit the Waikiki aquarium in Hawaii. I was deeply impressed by the beauty of the
reef tanks here. That started me reading magazines, books, and surfing the internet where
I obtained valuable information about reefkeeping from advanced aquarists such as Terry
Siegel, Randy Donowitz, Doug Robbins, Craig Bingman, etc. The tank of Gregory Schiemer
(seen in Eric Borneman's book) and the tank of Terry Siegel (seen in aquarium fish
magazines) inspired me a lot. Three years ago, I changed my fish only tank to my first
reef tank, where there was an excessive outbreak of annoying algae. Soon after, I reworked
the design and connected a mud refugium (24"x20"x20") to the main tank.
Philosophy/Methodology:
My aim was to construct a community tank (with a heavy bioload)
dominated with stony corals. I tried to experiment with high nutrient inputs and outputs.
I use high intensity lights and heavy feeding for energy input. On the other hand, heavy
protein skimming and periodical harvesting of macroalgae act as nutrient output. Besides
that, I used a 3 to 4 inch deep live sand bed, lots of live rock, which are assisted by a
well established mud tank for biological filtration. These methodologies have been working well
in my tank for the past two years.
Water Circulation:
I use 3 Tunze plus 1 Taiwan powerheads to provide random
currents throughout the tank. All of the powerheads are controlled by timers. All three Tunze
powerheads provide pulsating current. I also employ a Seaswirl oscillator connected to an
Iwaki MD-30 to provide turbulence. Furthermore, I built and use a Bruce Carlson Surge
Device which is placed on top of the tank. Every few minutes, a huge amount of water is
poured downward from the reservoir container above the tank. The water level of my tank
rises up and down periodically due to the surge device. The water current is ample
throughout the tank.
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Lighting:
On
my visit to the Waikiki aquarium, I found that they use natural sunlight, supplemented by
metal halides. Inspired by the tank in Waikiki, I use very intense lighting over my SPS
corals, certainly beyond the common recommendation of North America aquarists. Lighting is
provided by 6 metal halide bulbs: One 1000 watt 10,000k (BLV) bulb, two 400 watt 20,000k
(Radium) bulbs placed directly above the tank. Three 250-walts with 10,000k (BLV) bulbs
are angled towards the water surface. The photo period for all metal halides is12-hours,
except that the 1000-walt halides are only on 5 to 6 hours everyday. The bulbs are renewed
every 9 months. Therefore, my tank is extensively illuminated, requiring a certain period
of time for my coral to adapt this lighting scheme. The photo period is reduced
accordingly after I change bulbs. Lighting over the mud refugium is supply by a 150-watt
AB metal halide light which is switched on when the other bulbs are off over the display
tank.
Filtration:
Because I try to keep a lot of fish (more
bioload) in the tank three protein skimmers serve as my primary filtration system
-- One H&S skimmer, one AB skimmer, and one DIY 5 foot air driven skimmer. There is no
mechanical filtration of any kind. Activated carbon is used about once every two months.
Macroalgae is harvested from the mud tank periodically. The 3 to 4 inch live sand bed of
my tank and the invertebrates serve the purpose of biological filtration.
Calcium and additives:
A H&S kalkwasser reactor is used to keep dKH at 8-9. All the evaporated water of the
tank is automatically replaced by a calcium hydroxide solution from a DIY calcium reactor
during night time. Calcium hydroxide powder is mixed with DI water inside the reactor with
a magnetic spinner underneath to produce a good quality calcium hydroxide solution, and a
solution of strontium chloride is added biweekly.
Current Inhabitants:
Seventeen fish are kept in my tank. My fish population
includes a yellow tang (Zebrasoma flavescens),5 blue tangs (Paracanthurus hepatus),
a yellow tail demoiselle (Chrysiptera parasema), a foxface rabbitfish (Siganus
vulpinus), a clownfish(Amphiprion nigripes), 5 Bartlett's anthias (Pseudanthias
bartlettorum), and 3 Evan's anthias (Pseudanthias evansi).
Corals
There are many colonies of SPS corals such as Acropora, Pocillopora, Montipora,
Seriatopora, plussoft corals such as Xenia, Anthelia, photosynthetic
gorgonians, etc.
Clams
There are two 15 inch T. derasa and three 3 inch T. squamosa
Other invertebrates
I have a large population of blue legged hermit
crabs (Clibarius tricolor), one sea cucumber and many algae eating snails of genus Turbo, Nassarius species, etc. Also, there are numerous worms, pods, amphipods and mysids present in or on top of the sandbed.
Feeding Regimen:
I try to heavily feed my tank. I feed a variety of foods. Huge amounts of Artemia naupliiand DT phytoplankton are fed daily. Live rotifers are fed twice a week. All the Artemia
nauplii and rotifers are cultivated and enriched by Selcon or Zoecon. Nori is regularly
fed to the fish as well.
Maintenance Regimen:
I perform 5%
water change biweekly. I clean the front glass twice a weekly and clean the skimmer as
frequently as possible. Macroalgae is harvested regularly from the mud tank.
Chemistry:
ThepH is around 8.3, alkalinity 8-9
dKH, calcium ~420ppm,
S.G 1.025-1.027, Nitrate and Phosphate are present at low levels and haven’t been
checked for long time. Temperature is kept between 79F-84F. I use two powerful chillers to
control the temperature because the temperature in Hong Kong is very hot in summer.
Special feature of my tank:
My 15 inch T. derasas have been kept
for more than 2 years. They regularly emit sperm into the water column but they never emit
eggs. I guess that they are not mature enough. The barnacles and other invertebrate spawn
regularly. (The water of the tank will turn milky during the spawning event). The
biodiversity of my tank is great. Different types of sponges are visible everywhere. Many
copepods, amphipods and mysids can be found underneath the live rock. Bristleworms are
found all over the sand bed.
Problem encounters:
Nearly 90% of corals in Hong Kong are
imported from Indonesia. All of them are wild caught colonies. I encountered an RTN
situation after I introduced a wild SPS colony in to my tank. I also developed a Valonia
problem due to excessive feeding. Aiptasia may become a problem for me in the future. I have
observed that they sting at the base of some Acropora colonies. I am still at the starting
point of my road toward advanced reefkeeping. Many things still need improvement, but I am
willing to learn from my mistakes.
