Building A Zero Impact Marine Aquarium

Introduction

In this and the following articles I intend to document my experiences with setting up a 'Zero Impact Aquarium' (ZIA). This is my first venture into the world of marine aquaria, although I have kept freshwater plant tanks for some time. Nevertheless, if I as a marine novice am successful at this, then there is no reason why a seasoned reefkeeper should not do an even better job. Throughout, I will include the addresses of the sites from which I have obtained my information simply to avoid having to retype it here in condensed form. Well on that note, here is the first address. Here you will find detailed instructions on what a ZIA is and how to set one up.
http://www.garf.org/news18p1.html

Making The Cement Rocks (ARAGOCRETE tm.)

Upon deciding to go ahead with the project I began to research the making of cement rocks. This was very easy as the GARF web site has loads of info.

http://www.garf.org/news15p1.html

http://www.garf.org/news21p3.html

http://www.garf.org/news9p2.html

In addition to these I also found Tom Millers Web site very useful, in particular:
http://www.geocities.com/CapeCanaveral/Hangar/6279/RaiseCementRock.html

So, at the beginning of July 99 I began to make my first rocks. The recipe I decided to use was 1 part cement (Blue Circle Mastercrete from BQ), 4 parts Crushed Oystershell (Available from farm feed suppliers).
As a guideline, for every 8 cups of oystershell I added approx 3/4 cup of water and then added more water (slowly!) if needed. If you try this yourself, be prepared to experiment a little. To mould the rocks I used a bed of damp oystershell held in one of those large plastic storage boxes that you can buy in BQ. Over the course of several weeks I had made enough rocks to fill the tank I was planning to use. These included arches, caves, shelves as well as plain old rocks. Making the rocks is SO EASY and satisfying as you can slowly build up your reef, as you want it to look. What surprised me was how porous the finished rocks were. Water drains through them like a sieve, not how I imagine 'cement' to be.

Curing The Rocks

For curing, I bought a couple of black plastic dustbins. These were filled with tap water and as each piece of rock was ready I added it to the bin. Water was then changed daily.

Over the first weeks of curing the water would become cloudy quite quickly. After that period it would remain clear although I did notice a white deposit forming on the rocks (calcium carbonate I think). After eight weeks, a few spots of green algae began to appear on the rocks near the surface. It was at this point that I stopped the daily water change and let the water in the bin stand for 5 days. I then tested the pH and found it to be 8.2.

The next stage was the salt water cure. I simply added three cups of dishwasher salt to the curing water and let it stand for a week (as per Tom Miller articles). As expected the pH rose to 8.6. This water was replaced and the rocks received a further week of saltwater curing. The pH was again 8.6. At this point we were preparing for a house move, so packing etc. took priority and the rocks were simply left to stand in tap water again. Unfortunately our chain collapsed on the day of exchange and we subsequently lost the house. Very bad for us, but good for the rock, it got an extra six weeks of curing. The pH was now testing at 8.0. It was time to set up the tank.

Setting Up The Aquarium - The First Six Weeks

The tank was set up on 12th Nov 1999.

• Aquarium Size - 48x15x18
• Lights - Custom made hood, 2 x 4 foot Tritons, 1 x 4 foot Blue Moon,Each tube mounted in a reflector
• Skimmer - Seaclone
• Pumps - 2 x Maxi-jet 1200 powerheads
• Heater - 200W
• Substrate - 36lbs CaribSea Aragonite Seaflor Reef Sand, 4lbs Reef sand
• Water - Treated with API TWP deionising resin
• Salt - Instant Ocean
• Live Rock - Several small well encrusted pieces (approx 3.5 lbs)

The substrate went in first and I placed my table rocks onto this. These have only three points of contact with the substrate and support the rest of the rocks. The structure is very open, as it contains several cave rocks and arch rocks so water circulates through it well. The tank was then filled with deionised water treated using recharged API tap water purifier resins. Yes they CAN be recharged. Instant Ocean salt was used at salinity of 1.022 and the heater set to 77 degrees. It was left set up overnight to check there were no leaks or problems. I had already visited all the local marine stockists that week in a search for well-encrusted live rock and had them reserve various pieces for me. These were collected and placed among the cement rocks. One piece was crushed and sprinkled over the rocks and substrate to further seed them. One of the live rocks had a small spotted mushroom on it, while another had several zoanthids. These both opened, so I presumed the conditions were to their liking. After a few days I added 6 Turbos and a few bits of soft corals that were at the bottom of the invert tank at a local shop. They kindly let me have these for free. Some of the bits were already attached to small pieces of rock or shell so all I did was use Loctite Superglue Gel to stick these onto my cement rocks. The process was really easy:

• Dry off the rock the coral is attached to using kitchen towel.
• Remove the rock you wish to glue it to and dry that.
• Put a blob of gel onto one of the rocks.
• Hold the two together.
• Return to the tank.

I even glued one piece underwater. This involved putting the gel onto the rock the coral was attached to and quickly pressing it (underwater) onto the rock I wanted it to go on. The gel appears to form a skin on its surface the moment it goes into the water. When you press it into place, the skin breaks exposing the uncured gel, which then makes the bond. There were two pieces that were not attached to rocks; a sarcophyton and a cladiella (I think!). For these I used rubber bands to hold them onto a rock. Within an hour all the pieces had swelled up and extended their polyp's inspite of their ordeal. After a week, I began to see the first signs of a diatom growth (brown algae). Although the 6 turbos were doing their best to keep it under control, it was growing faster than they could eat it. So another visit to a different shop secured 6 more turbos and a few more freebies from the bottom of their invert tank. I was also able to obtain some coralline scrapings from a tank belonging to a friend of one of the shop assistants. After switching off the powerheads and skimmer I sprinkled these over the rocks and allowed them time to settle before turning the circulation back on. Over recent weeks I have added 3 red leg hermits and a further 4 turbos. These are really helping to keep algae at bay. In addition, my local shops have always been happy for me to have the 'bits' of corals broken from larger colonies, either for free or for a nominal price. I also obtained a number of cuttings from Jules Wilson who is on the ReefsUK database. As a result I now have quite a variety of soft corals, albeit very small ones, but (hopefully!) they will grow.

Livestock

The following corals were all identified using 'The Practical Guide to Corals for the Reef Aquarium'. Some of the cuttings are very small so their identification may be inaccurate.

• 16 Turbos
• 3 Red Leg Hermits
• 5 Colt corals- Cladiella sp.
• Yellow polyps - Parazoanthus gracilis
• Star polyps - Clavularia sp.
• Blue sea mat - Palythoa sp.
• Green Button polyps - Zooanthus pulchellus
• Brown Button Polyps - Zooanthus sociatus
• 2 Finger Corals - Sinularia sp.
• 2 Cabbage corals - Lobophytum sp.
• Spotted mushroom - Discosoma sp.
• Blue mushroom - Discosoma sp.
• Striped mushroom - Discosoma sp.
• 3 Varieties of Ricordea
• Finger Coral - Lobophyton sp.
• Yellow toadstool - Sarcophyton sp.
• Anthelia sp.

Growth of Coralline Algae

The first appearance of what I believe to be coralline growth occurred about four weeks into the life of the tank. This took the form of many small pin point red/dark purple dots on rocks in the brightest lit areas of the tank. Gradually these have grown in size. I am still not sure if this is coralline or another form of algae, largely because of its colour. In some areas it has turned brown while in others it has a more red/purple appearance. Only a few of the dots have a pink or purple hue to them. This spotting is now present (to a greater or lesser degree) on most of the rocks in the tank although most prevalent in the brightest areas. I have tried to photograph it, but without a macro lens the photos show very little.

Water Chemistry

From the outset I was careful to monitor changes in water chemistry. Ammonia, nitrite or nitrates have presented no problems, all have been reading zero and there has been no evidence of any significant cycling. The pH on the other hand has caused me some concern. I was very careful to ensure that my cement rocks had been thoroughly cured and I followed Tom Miller's advice of finishing with a saltwater soak. He recommends this in order to avoid a rise in pH that is experienced when freshwater cured cement rocks are first placed into saltwater. Anyway, during the first week the pH gradually rose from 8.4 to an alarming 9.0. I quickly carried out a 10-gal water change, which restored it to a slightly more acceptable 8.6 and promptly e-mailed Leroy at GARF asking for help. While waiting for a reply the pH began to rise again. In a bid to do something to halt it, I connected the carbon dioxide generator from my plant tank via a T piece to the air inlet of the Seaclone. My reasoning was that it would receive a CO2-rich air mixture and the carbon dioxide would react with the calcium hydroxide that was obviously leaching from the rocks. To my relief it seemed to work and the pH stopped climbing. A few days later Leroy e-mailed me, simply saying 'the pH will become stable, you don't have to worry'. So either my action helped or the pH simply stabilised. Either way, there was no loss of livestock. A suggestion made by Craig Bingham (in response to a post I sent to the Reef List) was to use a powerhead in the curing container. The extra circulation helps to drive out more of the pH raising substances. After a month I began to test for Calcium and Alkalinity using Salifert kits. Even though I had been following the Garf instructions with regards to which supplements and additives to use, my calcium registered only 150ppm!!! I immediately began to dose with more Seachem Reef Advantage daily while monitoring the calcium. Gradually it rose and with the help of another 10-gal water change is now around 400ppm.

Conclusions

So, one month down the line and I am very happy with the way my tank is developing. Apart from the initial problems with rising pH and low calcium, the tank seems to have reached some state of stability. All the soft coral cuttings are doing well and there has been very clear growth in many of them. Coralline algae has begun to appear on my cement rocks and the turbos and hermits have helped keep undesirable algae in check. Not only has this success been very rewarding but I have found it a very interesting process watching as the reef very slowly grows and develops. One impression I have gained, both from various Internet discussion groups and from talking to other reefkeepers, is that there is a reluctance to try GARF's 'Zero Impact' approach. I really can't understand why, given the success GARF clearly have with it. Just visit their web site and look at photos of their thriving reef tanks. I suspect the fact that it does not give you is an instant reef would put many people off. If you do not have patience then it certainly isn't the way to go, but for that matter neither is reefkeeping. However, I believe there is so much enjoyment to be gained from watching the gradual growth and development in a project such as this. Of course, there is also the real bonus of knowing that you are doing something (however small) to reduce the impact on the natural reefs. In several months I hope to write a follow up article detailing the progress of the tank. If in that time anyone has any questions concerning the Zero Impact Reef then feel free to contact me. Remember though, I am no reefkeeping expert but I'll help where I can and share what experience I have. Also if you are in the Dorset/Hampshire area and already have an established reef with soft coral cuttings to sell, trade or donate, please get in touch.

By Richard Rajski