Tracy Gray's (Mutagen)
Top down view
First, I would like to say I feel honored
to be included in the company of those who have preceded
me. This site has featured so many truly magnificent marine
aquariums that it's a bit difficult for me to find anything
to say or show that adds to the previous featured tanks.
But, I'll give it a try...
When setting up my 200 gallon reef, I
wanted to build a system that was maintenance friendly,
especially with regard to working in the aquarium itself.
I also wanted to build a system that did not require tedious
manual water top-offs or kalkwasser additions and the like.
Finally, I had already observed that the kaleidoscope of
colors provided by stony corals and clams is best viewed
from the top. So with those goals in mind, I built the following
The tank is a 200 gallon system with
a nominal 60 gallon sump and was set up in May of 2000.
Its footprint is 5 feet by 3 feet, and it is 2 feet deep.
To facilitate top-down viewing, the tank has an open top
with no center brace and the top is about 45 inches off
the floor. There is external circulation to the sump that
is split into a 30 gallon refugium, with the remaining 30
gallon volume being used to house the return pump, skimmer
feed pump, and chiller pump. This section also includes
the float valve that provides make-up water. All the ancillary
equipment except the calcium reactor is located behind the
tank since the stand is too low to house it. The area under
the stand is simply used for storage. The system includes
both soft and stony corals, but it is primarily stocked
with Acropora and Montipora. Almost every
coral in the tank was grown from a fragment, with only a
few being transferred from a previous 100 gallon system.
I would describe the fish load as moderate to slightly heavy.
As is common and appropriate, the higher light corals are
placed on the "prime real estate" nearer the surface
of the water, while the lower light corals are placed near
the bottom and along the outside perimeter of the tank.
Front overall view
Front overall (closer view)
Corner overall view
Side overall view
In the picture "side overall
view" above: The filtration equipment, sump,
and make-up water reservoir are located in the cabinet
behind the tank.
The lighting is a mix of four 175 watt
Ushio 10,000K and two 400 watt 20,000K Radium metal halide
(MH) bulbs. There is no fluorescent supplementation since
I feel the 20,000K Radium bulbs provide enough blue color
by themselves. Since the tank has a somewhat unusual footprint,
I tried to orient the lights to provide good coverage for
the entire area. To do this, I placed the (4) 10,000K bulbs
at each corner of the overhead canopy and placed the (2)
20,000K bulbs evenly in the center of the canopy. There
are MANY different combinations of light available, but
to my eyes, this combination has been the best. I have been
using this combination for the last year and a half and
have been very happy with the color and growth rates of
my corals. On the subject of lighting and coloration, I
can make some observations. Some of the corals with large
amounts of the green fluorescing pigments seem to express
that color better under the 20,000K lights compared to the
10,000K lights. They appear more fluorescent to the eye,
and I believe this may be due to various fluorescent properties
of the 20000K bulbs. In contrast, corals with a lot of red
pigment such as the pink Stylophora and pink Seriatopora
have shown this color better under the 10,000K light. I
guess this really just adds one more anecdotal story to
lighting controversy, but it is what I have seen, so I thought
I'd pass it along.
Green Montipora spongodes
The light canopy may be of interest to
some readers. It is built on a framework that not only supports
the canopy, but also provides a wooden border around the
edges of the tank. The canopy height can be adjusted by
means of a simple winch system made from sliding glass door
rollers and a closet hanger pole. All the parts were found
at Home Depot.
All the lights are on timers. I use the
mechanical type timers as opposed to the X10 technology,
since I have found the X10 to be insufficiently reliable
with my lights. The mechanical timers fit well into the
multiple outlet power strips that can also be found at Home
Filtration is biological and mechanical.
A homemade skimmer provides the mechanical filtration. Biological
filtration is via a deep sand bed, live rock, and a refugium.
About one half of the live rock is "artificial,"
being made from cement and a calcium carbonate substrate
or old reef bed material mined in Utah. In my experience,
the completely man-made rock takes at least a year to get
a good growth of sponges, worms, coralline algae, amphipods,
copepods, forams, feather dusters, etc. Also, only about
25% of the sand was "live" with the remainder
added as dry "dead" sand.
I do use carbon from time to time. This
is mainly aimed at eliminating any chemical competition
between the various animals. As is the case with most aquariums,
I don't know the degree to which chemical competition is
occurring, but at least the water is clear.
Plumbing and Other Devices
The external circulation exits the tank
through a pretty standard weir overflow. The only difference
is that I had the overflow built 4" from the back wall
to provide room to hide two MAG 950 pumps for additional
circulation. Since the overflow weir is on the back wall,
there are four sides for water to spill over instead of
the "normal" three. There is an advantage to the
additional overflow length: the change in height when flow
stops is minimized. The return flow enters from the back
of the tank on either side. It is divided by a splitter
box located behind and above the tank. This box also houses
an area where cryptic organisms tend to dwell. I think the
flow through this zone is too high to support the kind of
cryptic community I am trying to foster. Food is also added
into the splitter box from a "Rondomatic" automatic
feeder. I mention this because I have found this feeder
to be superior to some other designs.
Make up water is added from a reservoir
also located above and behind the tank. The make up rate
is controlled by a homemade float control valve which I
think is actually superior to the commercial units I have
seen. All of the make up water is saturated in calcium hydroxide.
I use a calcium reactor in addition to
topping off with calcium hydroxide. The reactor is also
homemade. I wanted it to be easy to duplicate, so I made
it only from parts easily found at Home depot or other hardware
stores. The result was a rectangular reactor that holds
more substrate for its size than comparable round units.
Of course, I still had to purchase the CO2 tank and regulator.
(DIY'ers should stay tuned though, because I am working
on an even simpler design.) The tank also requires a chiller.
I use a 1/3 HP chiller, and also use fans over the sump
to assist cooling. The tank will typically require 3 gallons
per day make up water.
The bubble counter is
made to be both a drip counter and bubble counter.
The tank is what I would call moderately
loaded with respect to fish. I have four tangs, and three
pygmy angels, a Pseudochromis splendidens, two algae
blennies, and a black cap basslet. Other mobile invertebrates
include three brittle stars, two sand eating cucumbers,
multiple hermit crabs and snails. I have also unintentionally
kept some unwanted invertebrates such as a Montipora
eating nudibranch and some Acropora eating flatworms.
As for the corals, I have multiple unidentified
and tentatively identified Acropora and Montipora,
Stylophora, Seriatopora, Pocillopora,
Turbinaria, Merulina, Echinopora, Hydnophora,
and some very recently acquired Porites. I have also
tried to line the bottom perimeter of the tank with various
Discosoma and zoanthids. The tank no longer houses
any Sarcophyton, which for reasons unknown to me,
do not do well in this system.
I try to exchange about 15 gallons of
water per week on a regular basis. I use a SeaChem vitamin
and amino acid supplement called Reef Plus. I add it anywhere
from daily to twice a week in no particular pattern. Is
it really useful? Who knows? As stated earlier, calcium
and alkalinity are maintained by use of a calcium reactor
and a 24/7drip of calcium hydroxide solution. The fish are
fed flake food twice daily by an automatic feeder. The tangs
seem to stay fat from this food, and whatever they can find
growing on the glass and rocks.
I guess this subject should embarrass
me since I am a chemical engineer, but I measure almost
nothing on a regular basis. When I do measure, I am able
to find no nitrate or phosphate with LaMotte test kits.
I do check the alkalinity once, or sometimes twice, a month.
I try to maintain a value of about 3.5 -4.0 meq/l. When
I measure calcium it is always between 450 and 500 ppm.
Again, I am not sure I can add anything
to the body of captive reef keeping knowledge, but I can
always add to the body of anecdotal observations.
I have had what I would call extremely
good growth rates with certain corals in this system. I
have removed/harvested around three square feet of plating
Montipora corals from this tank over the last two
years. In addition, I have taken dozens of Acropora,
Seriatopora, and branching Montipora fragments
as well. Some of these have been large enough to be characterized
as small colonies. On the other hand, I have found the growth
rates of certain Acropora and most of the soft corals
in the tank to be rather slow compared to other systems
I have observed. In particular, the zoanthids have grown
slowly, as has the photosynthetic gorgonian. Some Discosoma
have grown at what I would call a moderate rate, while the
Tonga blue "shrooms" couldn't outrun a glacier.
When comparing my tank to other tanks with 6500K bulbs,
I have observed that the 6500K bulbs do not seem to provide
any higher growth rates than what I am getting with the
higher Kelvin bulbs. The coloration is markedly different
and some corals do show more intense color with the 6500K
bulbs. Obviously, it's difficult to compare one tank to
another in order to compare lighting regimens. But if we
find a preponderance of people making the same observations,
maybe some general rules of thumb can be reached.
I believe the relatively slow growth
rate of soft corals in my tank is due to it being relatively
nutrient poor compared to tanks where soft coral growth
rates are high. Most of the "SPS" corals seem
to get a higher percentage of their nutrition from photosynthesis
compared to the soft corals. Then again, I have intentionally
placed them in the most intense light.
The physical set up of the system has,
indeed, reduced the amount of work needed to keep the system
running well vis a vis the routine maintenance jobs such
as adding top off water and alkalinity supplements, etc.
However, this has been offset by the work required to keep
the corals trimmed back. Another problem has been the slow
encroachment of zoanthids over the base of the "SPS"
corals. Even though shaded by the corals above them, the
zoanthids do eventually make their way up the bases of the
hard corals and subsequently kill off the lower tissue of
the stony corals. The carpet of zoanthids growing below
the "SPS" looks pretty nice, but eventually it
creates a fair mount of work in controlling where the different
If I were to build this tank again, I
would build it higher off the floor to make viewing from
the side easier. Then, I would build a small bench all the
way around the tank where one could sit or stand and easily
view from the top. I have been very happy with the canopy
and crank mechanism, and very happy with the open top configuration,
and highly recommend this layout for reef systems. The one
last thing I would like to be able to do is minimize the
total electrical power required for the system. If I could,
I would do this by using natural light through a light funnel.
Since I prefer a bit of a bluer look than sunlight above
the surface of the water, I would likely filter out some
of the orange and green light and hopefully also remove
some of the heat in natural sunlight. Or, better yet, when
I build that 30,000 gallon pool outside and turn it into
a reef I can... Guess I should wake up now.
I hope this article has been enjoyable
and maybe even provided some ideas for other aquarists.
If there are questions, I will do my best to answer in the
for the online magazine.
last two photos taken under "black light.