Gudmundur Geir's (DNA) Reef Aquarium

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Introduction:

It’s an honor being featured here on Reefkeeping Magazine and Reef Central with the tank of the month. My name is Gudmundur Geir, and I live in the Icelandic capital, Reykjavik.

It all began in 1990 with a space in my living room that needed to be filled. I bought a used 120-gallon tank mainly for aesthetic reasons and filled it with tropical freshwater fish and aquatic plants, but soon the hobby got hold of me and I was really enjoying it. After a year or two I built a 300-gallon tank and began keeping African cichlids. I always wanted to move into the saltwater hobby, but it was not an option since nobody here in Iceland was importing livestock in the early 1990’s. I had to wait until 2001 for my dream of a saltwater tank to come true. By then, two small pet shops had begun importing saltwater livestock on a small scale, so I made the transition even though their prices were astronomical, ranging from 2-20 times the normal U.S. prices.

Most of the knowledge I have on reefkeeping is from Reef Central and the web. I researched for months before starting my reef aquarium because I was determined to do it properly. I read with great interest what experienced reefkeepers were doing, but still I tend to go my own way.

Aquarium Profile:

320-gallon glass in-wall tank
Dimensions: 30”x 35”x 76”
100-gallon sump
6400g/h Tunze circulation pumps
100g/h sump return pump
750 watts 10,000K metal halide
160 watts of T5 fluorescents

Design:

In 2003 I bought a new apartment, and of course the main criteria for its selection was how well it would accommodate my in-wall tank design. The new tank was going to be built with simplicity in mind, and was planned to be a low maintenance tank lasting for at least 10 years. A lot of thinking went into its design and layout, and that was time well spent since only 80-100 hours went into the building, with me doing almost all the work. The whole project was rather cheap to build, costing around $4000, including skimmer and calcium reactor. The tank turned out to be a reefkeeper’s dream and now, 18 months later, there is little I would do differently if I had to do it again.

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The tank, which has a stainless steel frame, was the largest my new apartment would allow. Every guest that visits really likes its large dimensions. It is as deep as my hands can reach, and everything is easily accessible within it, and the depth allows for some creative aquascaping. The bottom shell fragment substrate consists of about 200 pounds of finely crushed seashells pumped from the bottom of a nearby bay. Because I didn’t want all of this sand to be hidden under piles of rock, I left a large, quite prominent open area that’s easily seen when viewing the tank.

I arranged the estimated 200 pounds of live rock to give a sense of dimension and to do something different from the conventional “reef wall.” I really like how it turned out, but I will need to make some changes as the corals grow and need more space.

The sump is a 100-gallon container with ample room for the skimmer, calcium reactor, macroalgae growth and marine life that’s unsuitable for the main tank such as a mantis shrimp, a rock boring urchin and a few fish I keep for a friend.

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Plumbing, Circulation and Top-off:

I gave this subject a lot of thought. Many reefkeepers go to such great lengths that they end up with a complex maze of pipes. That did not appeal to me, so I went the other way. One overflow is more than enough for this tank, and the standard Durso style standpipe with its submerged intake was the obvious choice. From there, the water flows directly through the skimmer and then to the sump. I installed a second overflow for surface skimming, as well as for safety, in case something was to clog the Durso. The return pump doubles, indirectly, as the skimmer’s pump. The flow is adjusted for the amount required by the skimmer to produce the best results since it is gravity fed. The plumbing is simple with only a few feet of pipes, and it works like a charm.

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The two Tunze circulation pumps, along with the tidal controller, do a great job maintaining a strong current throughout the tank, even behind the loosely stacked rocks. The automatic top-off mechanism, which adds freshwater directly from the tap, is synchronized with evaporation via float switches, for safety. There is no need for a fancy water purifier since the water here in Iceland is naturally pure. A large fan blows across the water’s surface to remove heat from the lights and to speed up evaporation.

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Left:  A programmable timer with four relays to control the lights, fan and automatic feeder.
Middle:  The Tunze controller is in the middle for the Tunze stream pumps.
Right:  A Tunze water level alarm with three float switches connected to
open or close the automatic top-off solinoid.

Filtration:

Water Parameters:
Calcium: ~440
pH: ~8.0
Specific Gravity: ~1.026
Temp: ~79º F

It's my firm belief that the fewer fish I keep, the more successful I’ll be with the reef, and the less the tank will get polluted. So, the only filtration is a Deltec skimmer and I make sure not to overfeed. I also grow macroalgae in the sump for a bit more nutrient export. I run a Deltec calcium reactor to maintain adequate calcium levels for good coral growth. Water changes are done sparingly. For an ”experiment,“ I went the entire first year without any water changes at all, and all went well as I had expected. The corals looked fine and seemed to grow well, but I noticed subtle changes for the better after the first water change, and I now do occasional periodic water changes. I use carbon most of the time.

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Lighting:

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Three 250 watt 10,000K metal halide lamps provide most of the lighting. I positioned them as closely as possible to the tank’s front rim, at an angle pointing slightly toward the back of the reef to have a little more light shining at the fish and corals, and less shadows, for optimal viewing through the front glass. Two pairs of 80-watt T5 actinic fluorescent bulbs add a slight blue hue to complement the metal halides’ color. The photoperiod is nine hours from noon for the metal halide bulbs, and 16 hours from 7:00 AM for the T5’s. Coral growth is quite good, but it would probably be a little faster with a longer photoperiod on the metal halides. The sump is lit with four normal output fluorescent bulbs from 6:00 AM to 10:00 PM.

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Inhabitants:

I have the utmost respect for all life, so when any animal in my care dies I ask myself if I’m doing the right thing by keeping it far from its natural environment in conditions that I can’t match, but can only simulate to some degree. Then again, life in the ocean is all about life, death and survival, and I feel I am doing my best to provide conditions that are as natural as possible.

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I get the most satisfaction from starting off with tiny coral fragments and nurturing them into glorious larger coral colonies. I plan to be in this hobby for many years, and aquaculturing is my preferred way of stocking the tank. It does not seem to be good business for the pet shops to sell small fragments, and these are available only from fellow reefkeepers. Fellow hobbyists with established tanks are so few in Iceland that fragments are very difficult to find. To me, keeping marine life is all about stability, and is a balancing act. I think I’m doing a fine job with a minimum amount of interference and lots of patience, to keep my tank alive and well.

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Fish:

Flushing pods from the shell...

Regal Tang:
A close “friend” of the Achilles tang who shares its interest in following people around who are close to the tank. He is skilled at picking up shells and flushing amphipods and other small crustaceans out of them.

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Achilles Tang:
This fish gets most of the attention, as its main goal seems to be to stay as close to me as possible when I’m viewing the tank or walking by it. It’s also a strikingly beautiful fish and looks like it’s always in a good mood. This fish never sleeps and is seen swimming back and forth even in total darkness. I was going to light the sump during the night, but changed it to daytime lighting to let this guy get some rest during the night.

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Copperband Butterfly:
I brought this fish for Aiptasia control and it did a perfect job of ridding the tank of the pest anemones. It’s also quite a feast for the eyes.

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Lawnmower Blenny:
This fish looks like Homer Simpson and is almost as much fun. It makes up for its lack of color with its unique characteristics.

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Bicolor Blenny:
During feeding when the Tunze pumps are off, this fish swims right into them. I don’t know if it likes to “play cool” or if it’s a stunt to impress the tank’s other inhabitants and me.

Neon Goby pair:
Inseparable, these fish stay close to one another and provide a valuable cleaning service, especially for the tangs.

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Maroon Clownfish pair:
This pair spawns every few days. Their home is the large long-tentacle anemone.

False Percula Clownfish pair:
This pair stays in the M. doreensis anemone, placed near the middle of the tank, and are subordinate to the Maroon clown female.

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Mandarin Dragonette:
Although I’ve had this fish for two months, I’ve seen it only a few times since it stays behind the rocks.

Firefish:
A very shy and inactive fish, the very opposite of the active tangs.

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Corals and Anemones:

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Various Acropora
Various Montipora
Euphyllia parancora
Euphyllia divisa
Favites
Hydnophora
Turbinaria reniformis
Fungia
Polyphyllia talpina
Briareum (formerly Pachyclavularia violacea)
Various corallimorpharians
Various sponges
Xenia

I’m far from where I intend to be with the corals. Foliose Montipora are my favorite, and a few large ones will dominate the tank in a few years, but zoanthids and soft corals do not fall far behind in their beauty. SPS and LPS are equally interesting as far as I’m concerned, and I’ll keep both to the very end. I do not want lots of small, different kinds of colonies I’m just waiting for the corals to grow and fill up the empty spaces.

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Stichodactyla haddoni
Macrodactyla doreensis

The anemones are my pride and joy, even though the long-tentacle one takes up almost a quarter of the tank. It deserves its own space and the Maroon clowns enjoy the protection it affords and will vigorously defend it. The green carpet anemones with their powerful stinging cells seem to be a death trap for other inhabitants. Nothing will escape them if caught. Still, I know for sure of only a starfish and two urchins that have fallen prey to them, but a few fishes are likely to have gone the same way. How they are able to eat urchins with long spines and suck their insides out of their test shows their ability to survive.

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Other Invertebrates:

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These are the most interesting marine animals, and I intend to have as many as I can within the space and ethical constraints of the tank. At the moment, there are two brittle stars, two cleaner shrimps, a rock boring urchin, a mantis shrimp living in the sump and around 100 hermit crabs and snails, to name a few. Unusual and fascinating invertebrates such as the Scutus slug and Ampheneura chiton that have regrettably died are the type of animals I’m looking for, although I hope to find species that have a better survival rate in captivity.

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Feeding:

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Just like humans need a variety of foods, the same applies to marine life. The fish are fed a range of flake foods and various pellets. They also get frozen Artemia and Mysis shrimp, and occasionally live Artemia. When I feed the anemones biweekly, shrimps and brittlestars get the remains of the food, consisting of octopus, shrimp, squid, mussel or other seafood. The tangs seem to have an endless appetite, so I feed often, but sparingly, each time. I have an automatic feeder on standby to be used when nobody is home for days at a time.

Highlights:

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The Maroon clowns spawn every few days and it’s unfortunate that none of the fry survive. It’s not for lack of attention from the clowns; their dedication for taking good care of the eggs is admirable. Unfortunately, I have not had the opportunity to properly rear the fry to juveniles.

The repeated spawning of the Green Chromis was a joy to watch, with violent, fast chases in between slow, gentle moments while spawning on the rocks. This kind of action is what makes reefkeeping so interesting.

I had a beautiful Montipora capricorni, that had grown quite large in just over a year, but it started deteriorating from the center and spread toward the edges at alarming rate. I hoped it would subside and the coral could be saved, but that was not the case and only a few fragments broken from the edges survived. Now I’ll have to wait at least another year for it to recover.

The Hydnophora and the Acropora had a gap between them which I thought was wide enough to prevent competition, and they had been that way for months when suddenly the Hydnophora struck with the full force of its mesenterial filaments, killing at least a third of the Acropora.

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I have two rock boring urchins, and I was quite happy with these free hitchhikers until they grew larger and started to knock rocks and corals over. Big corals and rocks up to two pounds get upended and the urchins have done some considerable damage, both directly and by knocking corals on top of each other. I've managed to banish only one of them to the sump, but the other stays hidden and can be removed only if it were dead, or attached to a rock.

One night right after the main lights went out a spawning event occurred (see pictures below), releasing huge amounts of eggs and sperm into the water column. I suspect it was some of the corals that spawned, but it was quite a show with only a few inches of visibility. The skimmer was extremely active, and I emptied many cups of odd looking organic matter. Even though the water didn’t smell foul, the two Green Chromis I’ve had for years perished along with two cleaner shrimps. The next night at the same time, another smaller wave of spawning occurred, but fortunately without any loss of livestock. Six weeks later, spawning occurred again for two nights in a row on a smaller scale, so perhaps this will be a regular event in my reef aquarium. I have yet to see any new life come out of the spawning events. I also learned a lesson while tending to fish belonging to a friend whose tank had leaked. Because of stress, the fish were soon infested with parasites that also moved onto my fish, killing one of mine and six of his.

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Spawning event.

Final Words:

Recently, I gained a great deal from a diving trip to the Red Sea in 2003. It broadened my understanding of marine life and I urge everyone who is able to visit and experience a coral reef in person to do so as it greatly enhances the experience and interest in the hobby of reef aquaria.

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You can follow my tank's development as it ages on my website.

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Feel free to comment or ask questions about my tank in the Tank of the Month thread on Reef Central.





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Tank of the Month - December 2004 - Reefkeeping.com