Building A Zero Impact Marine Aquarium
Part 1
It is now 9 months since the project began with the moulding of the first cement rocks, and 5 months since they were first placed into the tank and the water added. During that time I have had the pleasure of watching the dead rock slowly get colonised and grow into a thriving captive reef. So, to begin this update, I will look at how the rock has changed since being set up.
Cement Rock Colonisation
Upon setting up the tank my immediate impression was how sterile (and grey) the rock looked. This is how it remained for much of the first two weeks. Gradually patches of brown algae (diatoms) began to appear; life yes, but not really the sort I wanted. The 18 turbo snails that I added at this stage did a very good job of keeping this growth under control. The next life to appear on the rock was a green hair algae at around four weeks. This proved a little more difficult for the Turbos and hermits to control so I helped by picking out what I could by hand from time to time. At six weeks, while performing a water change, I divided the old water between two buckets. I then took out rocks and cleaned off the algae in the first bucket using a toothbrush, then rinsed it in the second before returning to the tank. Since then that particular algae has not returned, so either my actions helped or that particular bloom had simply run its course. Also at around four weeks, tiny reddish brown spots appeared on many of the rocks, which I mistook for coralline. Some later disappeared while many still remain. They did a lot to improve the appearance of the rock, making it appear less grey and cement like. Eight weeks in and I experienced a small outbreak of Cyano. At first I thought it was a brown slime that two Sinularia cuttings were producing as it was primarily forming on them. However, after seeking the help of others I felt it was Cyano. As it was only a small outbreak l left it alone. After about three weeks it too was gone. It was around this time that the rocks began to take on more of a green appearance due to a light algae coating. Coralline did not really appear until about twelve weeks in. Noticeable pinhead size patches developed on most of the rocks as well as the powerheads. These have continued to grow but quite slowly. It was around this time that that I began to notice various other forms of life setting up home in the rock. Every now and then I would observe various worms, copepods and amphipods moving around on and into the rock. The numbers of these have continued to grow and are now quite abundant. In addition there are various little miniature feather duster-like creatures as well as what look like very small barnacles. I've been trying to identify all this new life and have found Dan Maughmers Hitchhiker FAQ very useful. Much less welcome has been the appearance of a few aiptasia and a crop of valonia. The aiptasia have been controlled by injecting them with a concentrated calcium hydroxide solution, although two peppermint shrimps have now been added as these are supposed to be good aiptasia eaters. The valonia however, have had to be picked out by hand although in the long term I intend to try using an Emerald (Mithrax) crab to control these, that is if I can get hold of one locally.
Throughout the project I have followed the GARF guidelines closely, however in the light of experience there are things I would now do differently.
Making The Rock
I don't think I made full use of the fact I could control the shape and look of the final structure. Instead I tended to concentrate on the shapes and forms of individual rocks. These were then used to aquascape the reef. A far better approach would be to have the final look in mind and make the rocks to fit. As far as the actual forms go, rock tables are a great idea but make sure you make the legs of sufficient height. Once mine were placed in the tank and the substrate added I found I would have preferred a bit more clearance under the rock. Finally, use a powerhead in the curing bin. I'm sure the water movement will make the curing process much more efficient.
Seeding The Aquarium
When choosing your seed rock, try if you can, to get it from an established system that is free of Aiptasia, valonia and other pests. I say this because whatever is on the seed rock (good or bad) will eventually end up on and in your rock.
Water testing
I would strongly urge anyone following this approach to purchase Calcium and Alkalinity testing kits from the outset. For the first month I added supplements blindly following Garf guidelines. This led to a Ca / Alk imbalance which was only recognised when I started testing. Restoring this balance took time, as I did not want to subject the tank to rapid change. It was only when the balance was restored did I see an increase in coralline growth. I'm sure that if I'd picked this up earlier I'd have much more coralline right now. From what I have read, it appears that to achieve good coralline growth you need to maintain high alkalinity (above 8dKH). Certainly from my experience I go along with this.
Additives
The GARF guidelines recommend Seachem Products. I'm sure they are very good but personally I've found both Reef Advantage and Reef Builder to be very poor at dissolving and was never really happy at adding a cloudy suspension to the tank. I've since switched to C-Balance (a two part liquid concentrate) and occasionally add Kent Superbuffer when needed.
Tank Parameters
Averages of readings made in March.
- pH - 8.3
- S.G - 1.025
- Nitrite - 0 ppm
- Calcium - 400 ppm
- Temp - 77C
- Ammonia - 0 ppm
- Nitrate - 0 ppm
- Alkalinity - 9 dKH
Current Livestock
Since writing the last article the cuttings have grown and several of my early identifications have proved incorrect. To date, all but two of the corals (yellow polyps and Sarc.) have come into the tank as cuttings.
- 20 Turbos
- 2 TMC bred Common Clowns
- Green Star polyps - Clavularia sp.
- Brown Button Polyps - Zooanthus sociatus
- Blue mushroom - Discosoma sp.
- Striped mushroom - Discosoma sp.
- Finger Coral - Lobophyton sp.
- 3 Red Leg Hermits
- 5 Colt corals- Cladiella sp.
- Blue sea mat - Palythoa sp
- 2 Finger Corals - Sinularia sp.
- Red mushroom - Discosoma sp.
- 3 varieties of hairy mushrooms
- Sarcophyton trocheliophorum
- 2 Peppermint Shrimps
- Yellow polyps - Parazoanthus gracilis
- Green Button polyps - Zooanthus pulchellus
- 2 Cabbage corals - Lobophytum sp.
- 3 varieties of Spotted mushroom - Discosoma sp.
- Ricordea
- Xenia sp.
Conclusions
Almost six months and things are going very well. I never cease to be amazed at the amount of life there is in my once 'dead' cement rock. There are now two Common Clowns in the tank and the rock and skimmer seem to be doing a good job of keeping the water quality good. All the coral cuttings are growing well and those that multiply by spreading (Zooanthids, Palythoa, clavularia and mushrooms) have been doing so at a steady rate. I have even begun to try my hand at propagating. So far I've had success with cutting a few yellow polyps and a small piece of clavularia. Before too long these will be ready to trade.
It has been a steep learning curve for me and I must have read every reef tank related article on the Net (well, sometimes it seems like it!). In those moments of panic when things did not appear to be going well, the various discussion boards have proved invaluable. Indeed, without them I'm not sure I would have enjoyed quite the success I have.
I am really pleased with the way the tank looks although I had hoped by now to have a much greater degree of coralline encrustment. However since maintaining a higher alkalinity I have begun to see a much greater rate of growth. So, watch this space.