Aleksandr Pyndyk's (ealex) Reef Aquarium

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I would first like to thank Reefkeeping Magazine for choosing my tank as the Tank of the Month. It is a big honor for me.

I became involved in the marine aquarium hobby in 2000 after keeping freshwater aquariums for 20 years. My first reef aquarium was a 100-liter "stand alone" tank, to which I quickly added an overflow, a sump and a 100-liter refugium. In July 2002, I transferred this old system into my current 800-liter tank. The hobby has now grown into a "lifestyle," and gets most of my free time.

System Profile:
Location: Tampere, Finland
Main Tank: 185 cm long x 68 cm wide x 65 cm high, 800 L
Sump: 300 L located under main tank
Water Change Sump: 240 L
Coral Grow-out Tank: 300 L tank located in fish room

General Info:

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My main display tank contains 80 kg of live rock, almost all of which is still in its original position; everything else has grown up in this tank over three years. Now, little space remains for fish to swim or for corals to grow. If I start another reef aquarium, I will build smaller rock piles and put more live rock into the refugium. Click here for a slideshow of the tank's yearly progression since 2002.

I have a deep sand bed approximately 10 cm deep in the main tank and in the refugium. It has worked very well for three years now, and I believe it continues to work without problems.

Water circulation in the main tank is provided by a DIY wavebox (see below), three Tunze Streams (12000 l/h) and a return pump; currently, I use a Tunze 7400/2 (4000 l/h) as the return pump. In the coral grow-out tank are two 1000 l/h powerheads, which I plan to upgrade later to provide more circulation.

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DIY wavebox & controller

Water circulates in two loops between the system's tanks; first from the main tank through its overflow to the skimmer, then to the sump located under the aquarium, then to the refugium, and finally from the opposite end of the refugium back into the main tank. The second circulation loop goes from the main sump under the aquarium to the grow-out tank in my fish room, through the overflow to the water change sump in the fish room, and then back to the main sump under the aquarium.

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The refugium contains no circulation pumps. Water enters from one end over the separating wall, and on the opposite side is a return pump placed directly in the refugium. When planning this system I was afraid that a return pump in the refugium would suck too much plankton out of the water column, but it turned out that this solution works very well. I think it works better than would a return pump in its own section, in regard to collecting plankton.


Three 250-watt AquaConnect 14000K HQI bulbs, a 150-watt BLV 20000K HQI bulb, four 80-watt T5 AquaBlue 10000K and Osram/67 bluelight bulbs light the main tank. The main tank's photoperiod is 12 hours for the T5 bulbs and 11.5 hours for the HQIs.

Over the refugium are four T8 20-watt 6500K and a bluelight; photoperiod is 14 hours. The grow-out tank is lit by a 250-watt 14000K HQI bulb running on a 12-hour photoperiod.

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Water Parameters:
Temp: 26-29º C (78-85º F)
Salinity: 35ppm (Tunze conductivity meter)
pH: 7.9 - 8.3
Calcium: ~ 380-400ppm
Alkalinity: ~6 - 9dKH
Magnesium: ~1200
PO4: <0.015 mg/l
NO3: <0.5 mg/l

All biological filtration is provided by the live rock and the DSB. I do grow some macroalgae in the refugium, but did not find any "good" refugium macroalgae, such as Chaetomorpha sp. The growth is therefore not stable or regular, and I do not think that in my case it is significant with regard to biological filtration or nutrient export.

The refugium works very well at converting detritus and dissolved nutrients into live plankton. Because there is no circulation pump, the detritus falls down onto the DSB, which has no problem handling it, and there is a good zooplankton concentration in both the refugium's water and in its sand bed.

For mechanical filtration and nutrient export, I use a DIY "Beckett" injector type protein skimmer. I also use activated carbon and iron-based phosphate remover in a continuously running canister filter.

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DIY skimmer (left) and calcium reactor (right).


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For now, I do not use any supplements other than calcium and food. I do have some crushed coral in the calcium reactor, which provides some trace elements other than just calcium, but I plan to add pure calcium carbonate to the reactor during its next refilling to minimize additions other than food. In some of my friends' aquariums, which run without any additions other than food, I see much more natural coral growth and formation than in typical aquariums.

A DIY water level controller replaces evaporated water automatically. A peristaltic pump connected to a controller pumps water from a freshwater reservoir through a DIY limewater reactor (photo right) to the sump. A Tunze RO controller automatically refills the freshwater reservoir with RO water as needed.


I feed my tank heavily with a wide variety of foods, including amino acids and different frozen, liquid, dry and planktonic foods. A DIY phytoplankton reactor automatically supplies about 700 ml of Nannochloropsis sp. phytoplankton to the aquarium daily. The return pump feeds live zooplankton from the refugium to the main tank.

Corals and Invertebrates:

Stony Corals: many colonies of Acropora sp., Pocillopora sp., Montipora sp. and Seriatopora sp. Other corals consist of: Porites sp., Cyphastrea sp., Turbinaria reniformis, Hydnophora regida, Merulina sp., Blastomussa merleti, Caulastrea sp., Montastraea sp., Favia sp., Favites sp., Symphyllia sp., Lobophyllia sp., Physogyra sp., Euphyllia paradivisa, Euphyllia parancora, Goniopora sp., Trachyphyllia geoffroyi and Fungia sp.

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Soft Corals: Sinularia dura, Sarcophyton sp., various Zoanthus sp. colonies, Xenia sp. and Heliopora coerulea.

Giant Clams: Tridacna squamosa and Tridacna crocea.

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Mollusks: Strombus sp., Astraea sp., Nassarius sp., Turbo sp. and other snails.

Other Invertebrates: Various sponges grow from the live rock. Protula sp., Sabellastarte sp. and some other feather worms, two Lysmata amboinensis, two L. rathbunae and two Thor amboinensis shrimps, several pistol shrimps, one associated with the shrimp goby Amblyeleotris guttata, symbiotic coral crabs and shrimps, Echinometra sp. sea urchin and two Linckia laevigata sea stars. Additionally, I have two cucumbers, Holothuria edulis and Holothuria atra, the latter of which has divided into two individuals. I have noticed that Holothuria edulis does not do well when sharing the same sand bed with Holothuria atra, probably not because of a shortage of food, but rather I suppose it may be because some kind of chemical competition. Hence, I keep the Holothuria edulis in the refugium.

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There are also two Bubble-tip anemones, one of which has divided several times; the other is one of its "clones."

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Acanthurus leucostermon - 1

Siganus vilpinus - 1

Ctenochaetus strigosus - 1

Centropyge bispinosa - 1

Genicanthus semifasciatus - 1

Pseudanthias squamipinnis - 3 (♂ + 2♀)

Bodianus sp. (Peppermint Hogfish) - 1

Apogon cyanosoma - 1

Sphaeramia nematoptera - 2 (♂ + ♀)

Amphiprion ocellaris - 2 (♂ + ♀)

Synchiropus splendidus - 2 (♂ + ♀)

Chromis retrofasciata - 4

Nemateleotris decora - 1

Amblyeleotris guttata - 1

Gobiodon okinawae - 6

Gobiodon rivulatus - 1

Gobiodon quinquestrigatus - 1

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Concluding Remarks:

A few words about animals in the aquarium: Amphiprion ocellaris, Synchiropus splendidus, Chromis retrofasciata and Gobiodon okinawae spawn regularly in the tank, but I have not yet attempted to raise any of the fry. I bought most of my corals from my LFS despite their lack of bright coloration, because they were the only corals available, but they usually brighten up very nicely, given enough time. We have only one real marine fish shop in Finland, so when I started this hobby, I attempted to buy every coral I could find, regardless of its condition, because so few were available. The situation now, however, is slightly better. Rather than intentionally collecting only brightly colored species, I tried instead to nurture back to health every species I have. I am satisfied with most of my coral's growth rates in my aquarium, but I'd like to see more natural growth forms, and there is still much to do in this respect. I have never managed to successfully keep non-photosynthetic corals and some sponges, and I suppose this is probably due to irregular and inadequate feedings. I have three Goniopora, which are two to three years old, and I think the key to my success with them is placing them in the refugium from time to time.

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I try to learn constantly how to keep a successful and more natural system, so I test different things to find out which work better, but I do this in my main aquarium. Many things in my system change almost constantly, such as light and water flow, for example. I do not think that my aquarium is as successful as it could be if it were a more stable system; constant changes do induce some stress and have caused some problems, but also allow me to learn and get much more from this hobby, rather than just keeping a stable aquarium to decorate my living room.

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For more information about Alex's tank, visit his website here.

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

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