Reef Aquariums: A Feast for the Eyes
by J. Charles Delbeek

In the last six installments of this series I have gone over some of 
the basics with respect to reef aquarium components and the organisms 
that inhabit them. I think it only fitting to conclude this series by 
showing you some truly successful aquariums that meet the criteria for 
a "true" reef tank that I set out in the first article. Namely, that 
they closely resemble a section of a coral reef with all the requisite 
organisms in a harmonious balance.

Before I begin describing these systems I would like to briefly 
outline some of the factors that I personally feel are important in 
initially setting up a well-functioning reef system. These are my own 
opinions and are based on my experience as well as those of the owners 
of some of the systems described here. Your experiences may differ but 
I hope to convince you of the validity of these ideas by the systems 
described in this article.

There are various methods employed today in setting up reef systems, 
many of which are successful; some more than others though (Sprung and 
Delbeek, 1990). However, I feel that the most important ingredient, 
the one that will ultimately determine the appearance of the system
and the time taken to achieve that state, is the quality and amount of 
live rock used in a system. The reason for this is that it takes time 
for any system to reach a balanced state and the key to achieving this 
balance is the conditioning of the live rock. The better conditioned 
the live rock, the more stable the system. One method used to improve 
the condition of the rock is to let it sit in a unlit, well-filtered 
aquarium for at least a month (this is called "seeding" the rock). The 
rock is of course first stripped of all sponges and algae that could 
die-off and pollute the system. After about a month of seeding, the 
rock is placed into the intended reef tank. By seeding the rock in 
this way, any fouling organisms will have died off and the rock will 
have begun to develop significant encrusting red, pink and purple 
coralline algae growths. This rock is then used to build-up the basic 
structure of the reef. Specialized rock such as plant rock or anemone 
rock are not used until much latter, if at all. Seeding the rock in 
this way is not always practical for the hobbyist and we are often 
forced to place freshly collected rock into our systems. The removal 
of potentially fouling organisms becomes even more important in this 
case as the reef tank becomes the seeding tank. A complete description 
of the process of setting up a reef tank using seeded and unseeded 
live rock is given in Sprung and Delbeek (1990).

The source of rock is another factor that should be taken into 
consideration. I prefer to use "reef rock", that is, rock that has 
been collected from reef areas. These consist basically of pieces of 
coral and coral rock that have been broken off of the reef during a 
storm and have fallen to the bottom, where they are then covered, over 
the years, by numerous encrusting organisms such as sponges and 
coralline algae. To my mind this type of rock makes the most beautiful 
and successful reef tanks. It also cycles very quickly and stabilizes 
the tank rapidly. Inshore rock tends to be denser and is usually 
covered with numerous macroalgae, clams, mussels, crabs, shrimps and 
other unwanted organisms; to my mind less desirable but still usable. 

I cannot stress enough the importance of the quality of the rock in 
having a successful reef tank. Whether you use a trickle filter or 
only skimmers to filter your tank is irrelevant, if you have good 
quality rock with very little die-off, this will have a much greater 
affect on water quality than the filtration system. I feel that the 
importance of the filtering capacity of live rock has been greatly 
down played, and that of the filtration system has been, perhaps, 
overrated. One of the reasons why I have come to this rather startling 
conclusion is based simply on the wide variety of successful systems I 
have seen filtered by various means. The only common ingredient has 
been the quality and amount of live rock used. 

Some aquarists talk of using calcareous tufa rock or other, non-
calcareous, dried rock, however, I have yet to be convinced that a 
reef tank set-up in this manner ever comes close to a system using 
exclusively live rock. In addition, many reef organisms such as 
hermatypic hard and soft corals, require a calcareous base to settle 
on and do not colonize other surfaces very well (Stüber, personal 
communication, 1990).

Once the live rock has been introduced into the system, especially 
when using unseeded rock, one should wait at least 6 months before 
introducing any more living organisms. In addition, for the first few 
weeks, it is best to keep the lights off as intense lighting will only 
accelerate the growth of undesirable algae during this period of high 
nutrient levels (especially when unseeded rock was used). The reason 
for waiting is that the tank will be undergoing a series of dramatic 
changes. These usually consist of various microalgae and diatom blooms 
that could last as long as 4 months or more, not to mention the 
nitrification cycle that occurs within the first few weeks. If you add 
corals etc. immediately, you may lose some specimens due to the 
microalgae. One could add macroalgae at this point if desired, to help 
cycle excess nutrients out of the tank quicker. After a period of 4-6 
months you will notice that the tank will start to look very "fresh" 
and it will have a healthy "glow" to it. I'm sorry but I don't know 
how to better describe it. Those successful hobbyists out there will 
understand what I am talking about, it is almost as if one develops an 
empathy with their aquarium and can tell at a glance when things are 
going well or poorly. Once your tank has achieved this state it is 
time to start adding more organisms. Some start by adding a tang or 
two to help control algae growth while others suggest that fish should 
be the absolute last addition so that various organisms on the rock, 
and in the system, can have a chance to multiply. If you were to use 
well-seeded rock the times mentioned above would become dramatically 
shorter. 

The initial quality of the rock is also a very important variable in 
the cycling time. One often hears how quickly a tank cycled and how 
little ammonia was produced, the filter is often given the credit but 
I feel the quality of the rock plays a much more significant role than 
previously believed.

How much rock should be used is a commonly asked question. The old 
rule of thumb has been 2 pounds of live rock/gallon. As I explained in 
my first article, I do not think that this is a viable rule due to 
differences in rock density (Delbeek, 1989). Another problem is that 
this old rule often results in people trying to cram in as much rock 
as possible to reach the "ideal" weight of rock. The danger in this 
approach is that water flow around the rocks becomes greatly 
restricted and detritus will eventually accumulate at the numerous 
contact points of the rock which could result in serious problems 
later. It is much better to build a loose arrangement of rock such 
that there is as little contact as possible between rocks and between 
rocks and the substrate. This will greatly facilitate cleaning and 
water quality as the tank ages not to mention better circulation of 
oxygen-rich water around the rocks. Don't forget, many of the 
specimens you will add later come on their own rock, so space 
allowances must be made for these too.

Even with all these precautions it still takes time for a system to 
mature. This can take anywhere from 1 to 2 years. Yes years! One of my 
German pen-pals refers to a system less than 2 years old as "young". 
Once this "steady state" has been reached the system almost, other 
than routine maintenance, appears to run itself. A common symptom of 
this state is that the amount of ozone required to maintain a set 
redox value gradually decreases to extremely small amounts. I believe 
that all of the systems in this article have reached that stage.

The first reef system I would like to present to you belongs to John 
Burleson (of J.P. Burleson Inc.). John has been an extremely dedicated 
hobbyist for over 10 years. In the last two years that I have been 
following John's aquariums I have been constantly amazed by the size, 
beauty and health of the organisms John has been able to keep and 
grow. His skill as an aquarist is irrefutable and is evident in the 
photos of his system. The aquarium is 150 gallons in capacity and is 
filtered by a twin spray bar Pisces trickle filter filled with Dupla 
Bioballs(TM). Ozone is injected into a small skimmer installed in the 
sump at a setting of less than 5 mg/hr, just enough to prevent the 
build-up of yellowing compounds in the water. Redox hovers around the 
350 mV level. Additional filtration consists of a Tunze 215 power 
skimmer and activated carbon. Lighting consists of three VHO Philips 
actinic 03 and three VHO Sylvania daylight fluorescent lamps which 
come on and go off in stages. Water changes are performed on a monthly 
basis and freshwater, passed first through a reverse osmosis unit and 
then through a deionizing column, is used for topping-off evaporation. 
A chiller is employed to keep the temperature in the mid-70's. The 
only additions that John regularly performs, that I am aware of, are 
fish food and calcium chloride to maintain the calcium level for the 
corals and calcareous algae. None of the invertebrates are fed 
directly. 

The tank contains numerous soft corals (e.g. Xenia, Anthelia, 
Sinularia etc.), hard corals (Catalaphyllia, Trachyphyllia etc.), 
mushroom anemones (Discosoma sp., Ricordia floridans), gorgonians 
(Pseudopterogorgia sp.), tridacnid clams (Tridacna derasa, T. 
squamosa), leather corals (Sarcophyton sp.), zoanthids, various 
species of shrimp. Fish include a Red Sea Purple Tang (Zebrasoma 
xanthurus), a Red Sea Pseudochromid (Pseudochromis dutoiti), a 
mated pair of Ocellaris clowns (Amphiprion ocellaris), a Flame Hawk 
(Neocirrhites armatus) and several damselfish.

The second system I would like to describe belongs to Mr. D. Stüber of 
Berlin, Germany. Mr. Stüber has been in the hobby for over 20 years 
and his system is representative of the so called "Berlin School" of 
aquarium keeping. Two 250 W HQI(Registered) metal halide lights 
(replaced every six months), supplemented with blue fluorescents 
(Actinic-type bulbs), are used on his 700 L aquarium. The lights come 
on and go off in stages over a 13 hour period. Filtration consists 
simply of a small overflow which drains into a sump. The sump contains 
a few small compartments for prefiltration and one for calcareous 
gravel in which denitrification is believed to occur. Water is pumped 
from the sump into 2 four foot air-driven skimmers (COMPLETELY cleaned 
everyday) from there it flows back into the tank. These skimmers were 
designed and built by hobbyists in Berlin and have been used for many 
years. Air is pumped into the skimmers such that a total of 700 L/Hr 
of air enters the skimmer which is approximately one litre/hour of air 
per litre of aquarium water. There are 6 Tunze Turbelle water pumps 
located in the tank itself to promote vigorous water movement (Stüber, 
1989). 

There are basically two types of aquariums kept in Berlin; soft coral 
tanks and hard coral tanks; fish are more of an afterthought. Water 
chemistry is of utmost importance in both types of systems. Mr. 
Stüber's water chemistry parameters are as follows: pH 8.3, nitrate 
less than 10 mg/L, nitrite 0.05, KH 8, temperature 26oC and specific 
gravity 1.025 (Stüber, 1989). Somewhat surprising perhaps, is the 
redox which varies between 180 and 195 mV as measured with a silver 
calomel probe. However, it is very difficult to compare redox values 
from one tank to the next due to innumerable variables such as probe 
type and pH, so any comparisons between aquariums are almost useless. 
Ozone is not used in this system. Water changes are performed at the 
rate of 5% per month. Activated carbon is used every three weeks for a 
period of a few days and is then removed.

Hair algae must of course, be totally absent before any hard corals 
are introduced to an aquarium. Macroalgae (Caulerpa taxifolia) are 
used to help keep microalgae under control as well as numerous snails, 
sea urchins, starfish (all of which help scavenge the aquarium too) 
and tangs, specifically the Yellow Tang, Zebrasoma flavescens 
(Stüber, personal communication, 1990).

At present the system contains over 24 specimens of hard corals 
representing 11 different species. These specimens are all growing and 
spreading over the rock. Mr. Stüber uses both calcium hydroxide and 
strontium chloride solutions (see Sprung and Delbeek (1990) for 
detailed instructions on their use) regularly in his aquarium and you 
can easily see the results of these additions in the magnificent 
coralline algae growth and the remarkable hard coral colonies! Species 
of hard corals growing in this system include Acropora formosa 
(grows at the rate of over 2 cm/year), Echinopora lamellosa, 
Seriatopora sp., Porites sp., Millepora sp., Favites sp. and 
Pachyseris sp. (Stüber, 1989). The tank contains also Tridacna sp. 
clams, zoanthid colonies, mushroom anemones and other soft corals. The 
first piece acquired, Acropora formosa, was introduced into the tank 
in 1983 and was about the size of a quarter. Over the years various 
pieces were broken off and given to other hobbyists in Berlin. These 
"daughter" colonies have grown equally well (Stüber, 1990). The 
specimen of Pocillopora damicornis has been similarly distributed amongst 
hobbyists in Berlin. This coral has also spawned several times with 
one of the planula larva actually growing into a new colony. One point 
that Mr. Stüber makes quite clear is that no other corals, especially 
mushroom anemones (Discosoma sp.) and zoanthids, should be allowed 
to come into contact with these hard corals as they will sting the 
corals eventually killing them (Stüber, 1990). 

In the next artcile I will provide you with more information on the 
initial set-up of a reef system and we will look at the reef systems 
of John Payter, Mike Paletta, Julian Sprung, as well as my own. 

References
Delbeek, J.C. 1989. Reef aquariums: An introduction. AFM 2(2):24-33.

Sprung, J. and J.C. Delbeek 1990. New trends in reef keeping: Is it 
time for another change? Freshwater and Marine Aquarium 13(12):8-22, 
180-184.

Stüber, D. 1989. Wat doen ze daar in Berlijn eigenlijk? Het 
Zee-Aquarium 39(11):217-223.

Stüber, D. 1990. Rifbouwende steenkoralen in het zeeaquarium/1. Het 
Zee-Aquarium 40(5):107-110.