This aquarium is unusual in many ways. Its dimensions are not what people are used to, the animals are splendid, the equipment is impressive, and the philosophy driving the project is quite interesting!

This article was originally published in the French language by recifs.org, a leading, quality-driven, internet publication from France:

Editor’s Note: Check out the article’s Photo Album to see more pictures of this tank.

With a passion for coral reefs, Gabriel began his reef aquarist’s life six years ago with tanks getting bigger and bigger. He finally maintained two interconnected tanks (1,000 and 600 liters – 260 and 160 US Gallons). The first focused on SPS, the other on LPS. After a move to a different house in 2002, he decided to convert is garage into a room dedicated to a large aquarium. This was the beginning of a formidable bet: the tank should be 6 meters (20 ft) long, 1 meter (3.3 ft) wide and 0.65 meter (2.12 ft) high!

Technical Features And Maintenance

The display tank holds 4,200 liters (1,110 US Gallons). It has an overflow box containing three 40 mm (1.6”) pipes, all leading to a decanter. This decanter was engineered following the concepts detailed in an article (1) by Joffrey Dislaire. Its volume and length was computed from the overflow characteristics so that sediments would be allowed to settle on the bottom. A set of valves allows the overflowing water to be redirected straight to the sump during maintenance.

The decanter then directly force-feeds three H&S skimmers. These skimmers are equipped with two Eheim pumps with needle wheels, and were customized by the manufacturer with bigger inlets, so that flexible 40 mm PVC tubing could be used.

Another singularity of these skimmers comes from the air they are using. All air inputs are connected to a PVC pipe leading outside the house; this is a real advantage, as a majority of the gas exchanges in an aquarium setup happen in the skimmers (2). Ozone is also injected (30 mg/h), using a Red Sea Aquazone Plus device. The water is also going through a 55 W UV system from De Bary Aquaristics. The skimmers have their outputs directed towards a low-rise sump, used for small equipment (heaters, probes, level sensors, etc…). The water return is powered by a Black Devil 12,000 l/h (3,200 GPH) pump.

A shed located outside the house is the home of the water reserves, for sea and fresh water, and of the Teco chillers. Water changes are easily done from the decanter using a dedicated plumbing system and a pump.

In order to maintain calcium and alkalinity close to natural values, three Nilsen reactors (Ratz) and a calcium reactor (Aquacare 4) are used.

The reactor’s plumbing is currently being revised as it has proven difficult to find a correct location for their effluents, with a negative impact on their efficiency.

Water movement is provided by tunze powerheads: six 6100 Streams and two 7410 Turbelles are used. The streams are positioned so that they create a circular flow, and the Turbelles are complementing them while fixing some issues due to the rocks disposition. This setup is as well being revised as it is too strong in certain places, and too weak in others. Claude Hug, from tunze, nicely offered his expertise in pumps setups. His comments are eagerly awaited!

Light is provided using nine metal halide pendants. Each pendant is equipped with two 400 W / 10,000 K bulbs. One pendant has a mix of 10,000 and 14,000 K bulbs. Some corals seem to react differently, color-wise, under the different setups. Ten blue fluorescent tubes (Osram 67) complete the lighting system and provide transitions.

So that sediments could be controlled, all the live rocks are elevated using egg crate. A dedicated Black Devil pump in a closed loop flushes the sediments using plumbing located behind the rocks.

The rock-work is relatively flat, but features some rifts, ridges and other pinnacles. For aesthetics, a layer of sand, 7-8 cm (2 to 3”) deep, has been placed around the rocks. It also offers a habitat for various pistol shrimps (Alpheus sp.).

Maintenance is simplified through the automation of most of the recurrent and annoying tasks, like water top-off, supplementation, water changes, and temperature and sediment control. Most of the measures are made using specific instruments (tunze pH-meter, redox and temperature sensors) and a specialized computer (IKS Aquastar). Indicative water parameters are:

• Temperature: 26°C
• pH: 7.9 – 8.2
• NO2 and NO3: Not detected
• PO4: Not detected
• Calcium: 420 mg/l
• KH: 10

Animals

The system is engineered for keeping a high number of SPS corals, with nutrients levels in the water as low as possible, and a strong lighting source in order to sustain the coloration of the corals. The results are clearly positive, with many examples of brown frags acquiring intense coloration after a few weeks or months in the new environment. Their previous owners simply cannot believe the results! Many Acroporas are represented, as well as a selection of Seriatopora, Stylophora and Pocillopora. Gabriel knows the history of each of his corals. He always has a thing or two to tell about a specific animal, some of them having lived in many aquariums for as long as ten years in captivity.

As far as fishes are concerned, the tank’s size allows the maintenance of some species in conditions that are – at last! – adapted. More that fifteen species of surgeon fish live in harmony in this large aquarium, showing intra-specific and inter-specific behaviors that are quite interesting to witness. Juvenile individuals tend to mature quite rapidly too.

This rapid growth is also applicable to the many specimens of Angel fish hosted in this aquarium. A few mated pairs even formed: Pomacanthus imperator, Centropyge loriculus, and Apolemychtis xanthopunctatus. Some of them tend to feed off corals a little bit, but they rarely attack the same colony, so damage is not permanent.

Some associations failed. A pair of adult Naso elegans was introduced, but, after a month constant fighting, initiated a mortal disease for one of them.

A pair of Labroides dimidiatus established a cleaning station on one side of the tank, and many large fish come regularly for a clean-up. One wrasse can be seen penetrating entirely inside the Naso’s mouth on a regular basis. The surgeon fish completely changes tint, getting lighter, indicating his acceptance. Many smaller fish were introduced, mostly in sexual pairs, like Amblyeleotris randalli or Gramma loreto, each finding a proper habitat somewhere in the tank. Gobies are associated with Alpheus sp. shrimps, like A. bellulus. Other invertebrates live in this captive ecosystem, like that group of Astropecten typicus that shows regular reproductive behaviors. There are as well the Dollabela auricularia, 4 to 5 years old, with oral discs as large as 20 cm (8”).

It is difficult to name all animals hosted in this aquarium, as well as describe their particular behaviors, but their well-being is obvious, mainly due to the tank’s volume. Questions can be raised about the maintenance of certain species in sizes that are more often associated with our hobby.

Ten questions

recifs.org: Hi Gabriel. Thank you very much for the presentation of your impressive aquarium. Could you tell us about what motivated the creation of a system with such a volume?

Gabriel: Fish happiness above all else! Whatever the animals you are deciding to keep, I think that their maintenance conditions should be the main worry. When confronted to the enormous free space that fish have available to them in the wild, I didn’t hesitate too long. Available length for swimming is a key element for the proper maintenance of some species ( Acanthurus sohal for example). I chose the maximum length possible with a single glass pane, 6 meters. As for the more standard width of 1 meter… well… it is already difficult to reach the back of the tank! The 65 cm height allows strong lighting even at the bottom.

recifs.org: What was the biggest disappointment?

Gabriel: None as far as the technical specifications are concerned. For sure, a lot of time, maybe too much, has been spent on that topic alone. Regarding the animals, the loss of one of the Naso and the xanthopunctatus’ jump saddened me most…

recifs.org: What is you biggest satisfaction, or what makes you most proud?

Gabriel: The results are far beyond my expectations! The system is nevertheless still young (a bit more than a year old by now), but the good health of my animals, the corals’ rapid growth and the reproductive behavior of many mated fish pairs are elements that I am strongly enjoying every day.

recifs.org: What will you change or correct in the short or medium term? Why?

Gabriel: As you mentioned in the article, water movement needs changes, even if the current results are not all that bad. They can be improved, and I am thanking Claude in advance for his experienced advice. The plumbing for the calcium supplementation needs work too.

recifs.org: With the experience you acquired, what would you recommend (or warn against) to aquarists that are planning their new setups?

Gabriel: I’ll repeat what my good friend Joffrey says all the time: “Compute everything”. A system is born on paper… Everything must be sized properly; minimums, and more importantly maximums. A few examples: heaters’ capacity should not be above what is required by the volume, the fresh water reserve should not be able to “rinse” the system if there is a problem with the top- off equipment… There are many more things that must be anticipated. I believe that the rule of “what can do more can do less” is dangerous when something goes wrong. Experience can also make mistakes less extensive.

recifs.org: What animals are your “preferred pets”? What are their stories?

Gabriel: They mostly all have some history! Some colonies of Acropora traveled from aquarium to aquarium, starting from my previous systems, and came back to me after I had lost the mother colony. There are the very small frags that grow into true museum pieces after some time. There are as well the corals bought brown at an LFS that turn into intensely colorful colonies. As far as fish is concerned, when a mated pair is formed, it automatically creates something different; you become even more attached to the animals!

recifs.org: This must be the thing everybody is wondering about: how do you achieve such coloration, what is your secret?

Gabriel: I think there are no secrets. Above all else, there is the combination of light, water movement and skimming that is creating conditions as close as possible to the wild. Proper feeding is also a key element in my opinion. Once a month I make a home-made “soup”, composed of many sea shells, mollusks and fish meat. The only issue I have with heavy and rich feeding is when some parasites are present, like Anamonia majano or Aiptasia. Their spread is then greatly accelerated because of their opportunistic nature. I fed a lot of Artemia in my previous aquariums, but suffered a great Aiptasia invasion as a consequence. I also add a lot of strontium and iodine.

recifs.org: What are your next projects?

Gabriel: They are many! But first I need to finish the current project at hand. Finishing, water movement, calcium supplementation… There is much that needs to be done! Other than that, I’m starting a plankton culture. My goal is to attempt the full growth of young fish acquired through natural reproduction. We may discuss that later, in another article.

recifs.org: Are there additional animals you wish to keep?

Gabriel: There are always species you would like to possess! But is it really important? Well…. maybe a small colony of Acropora echinata would be nice, now that you are asking….

recifs.org: Is there anything you would like to ask? Anyone you would like to thank?

Gabriel: Many thanks to my friend Joffrey Dislaire. Without him I would not have achieved the same results. His contribution comes close to the zero- default! It is too bad he took some distances from the hobby. I also would like to thank Christian Courcier for his advice when I was a beginner.

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Photography: Hervé Rousseau

Video: Nicolas Will

References

1. Tout savoir sur la sédimentation – Joffrey Dislaire – Aquarium Récifal – 2001
2. Indoor air quality – Robert Jourdan – Advanced Aquarist Online Magazine – April 2002 – http://advancedaquarist.com/2002/4/short