Fishkeeping
Written by Monday, 27 October 2008 00:00
Once upon a time – not in the west but in Kalmthout, Belgium - there was a man (Staf) with a weakness for fish. These fish happen to be Malawi cichlids. Luckily he got married to a lady (Linda) who has learnt to love these fish throughout the years. Sometimes a marriage has a strange chemistry. After building several tanks both for ourselves and for friends it was time to start with the big work: building, for us, a mega tank. This was necessitated by a number of reasons. To note but two, our fish collection was expanding to include more rare Malawi cichlids while at the same time more and more people were contacting us to get good quality fish. We needed a big tank to house them.
Yes, we wanted a big tank. But where? After some sleepless nights we decided to reorganise the garage. Our reasoning was simple: if the garage was big enough for two cars then it was big enough for a mega tank. Having considered all the particulars we decided that in the given space we could make a tank 2m by 1,60m (floor space); the height would be 1m. The total volume of our mega tank was thus coming to a considerable 3000 litres of water.
Once you decide to start a job like that you need to keep focussed on your final goal. A tank does not just materialize. To get there one needs to do a number of tiring, boring or even "dirty" jobs. Our first job was the "dirty" one, namely to weld the rack which would support the footprint of the tank. Some Malawi cichlids are called black face; during the welding Staf earned himself the same nickname.
We then had to work out how we would build the tank itself on the rack. Tanks of similar sizes are usually built in situ. As the rack was in a corner it wasn’t possible to walk around when we would be glueing the glass. We decided to construct a support frame using plywood and multiplex. We could thus rest the glass panels on the frame while glueing them together. As you can see in the pictures things started to look massive.
When we were done with the construction of the support frame we calculated the exact measurements for the glass as well as the dimensions and positions of the holes that had to be drilled for the pipes. For the thickness of the glass we consulted Frank Panis (MCH Portal) because his kitchen tank has the same height as the tank we were about to build. Professionals recommend the use of 19mm glass for tanks of similar dimensions to ours but we decided that the 15mm Frank used for his tank would be sufficient. This would save us a whole lot of money as glass prices rise considerably with higher thickness requirements. Having said that, we were adamant we would not compromise the safety of the tank; to make up for the decrease in thickness, we would glue wider strengthening bars (30mm instead of the recommended 15mm) around all the glass edges to stop the glass bowing.
Before the glass was delivered we connected the pipes that were to go under the tank, i.e. filtration and drainage). The drainage pipe leads to the drains of the house thus making water changes easy; we will not have to mess around with hoses or clean up the inevitable water spillage, which on occasions becomes flooding.
Two days later the glass was delivered. You would think it’s very exciting when the glass arrives but in fact the tension increased by the minute to start with the big job.
Glueing time. The first panels, which were to go at the back of the tank, were heavy but quite easy to position. We placed them against the support frame and glued them together. We then put the bottom panels in place. We ordered two panels for the bottom of the tank to eliminate the possibility of one big panel bowing and eventually exploding from the pressure exercised on it. The bottom panels were joined together with silicone. It was imperative that the edges of these panels were spotless clean prior to them being joined together as they were cut to be a tight fit in the corners. Any small piece of dirt that remained on the edges prior to them being joined could result in the tank leaking.
We let the silicone dry for a day, then glued the third side panel (2mx1m) on. This was a tricky business because it just about fitted on the remaining surface of the construction supporting the footprint of the tank. In fact, there was only 17mm of space available and that was the exact space required to fit the thickness of the glass plus the silicone strip. If the panel did not go exactly in place there would have been a "cruel accident” but luckily everything went well. At this stage we did not glue the front panel to the tank as we wanted to have access to the interior in order to do the decoration.
Next we put the strengthening and bracing bars in place. The panel with the tape on was removed later; it was placed there temporarily to hold the strengthening bars in place while the silicone was drying. After these had dried we’ve put the bracing bar across the middle of the tank; this alleviates the danger of the sides bowing due to the water pressure.
As the tank was still empty we positioned the lights - 2 HQI lamps 250W each - and connected the pipes. The lighting looked good, though the trailing wires were neither safe nor aesthetically pleasing. We left tidying these up for later and instead went on to place polystyrene on the bottom of the tank; this would be the base on which we would put the rocks. There were about 750 kg of rocks to come so it was necessary to protect the glass from their uneven edges.
The next step was to glue the background in place. We used Back to Nature slimline background to avoid taking too much space; it was important to leave as much swimming space as possible for the fish. With the background in place we went on to make rock formations for the fish to swim through. It was an exercise we will both remember for a long time as a lot of the rocks were weighting about 60 kg each!! Incidentally, the shaft you see in the back between the rocks (second photo above) is the overflow for the biological filter under the tank.
Once the rocks were in place we cut out the polystyrene which was extending beyond the rock formation and put 150 kg of Malawi sand into the thank. The decoration was complete so we subsequently glued on the last (front) panel.
The next day the last bracing bar had to be glued to place so we had to get into the tank. We can assure you, a normal leg isn’t long enough. If we ever need to do this again we will plan a prior visit to a plastic surgeon ...
The setting up part was finished; that included the best solution we could find to tidy up the wiring of the lights. This is how the tank looked:
It was only then that the really difficult part started. We had to wait for ages until the tank was dry and strong enough to be filled with water. It took about 28 days, which seemed like an eternity, before we felt it was safe to fill it up. From the moment we turn the tap on it took 3 hours to fill the tank up completely. When this was done we started the system pump as well as the Koralia streaming pump which was placed inside the tank.
The photos below were taken the day after the tank was filled up for the first time. Spot the problem ... yes, the tank was foggy. It was only when we saw it like this that we realised we had forgotten to rinse the sand. Oh well, even experts make mistakes! A few days later the water started clearing up and we decided to add the fish.
About 75 fish were added and for the first few days everything went well. But then a Copadichromis pleurostigma started to show off and caused a lot of stress to the other fish. We lost a few big specimens, something we never expected. It wasn’t obvious that fish who formerly swam together in a 1000 litre tank would encounter compatibility problems when moved to a much bigger tank.
The tank cleared up completely soon after and looked absolutely stunning:
Two months later we decided to put some additional rocks in the foreground, plants (Vallisneria spiralis) and some more fish. The inhabitants of the tank are: Copadichromis pleurostigma, Mylochromis melanonotus, Cyrtocara moori, Placidochromis phenochilus 'Tanzania', Placidochromis phenochilus 'White Lips', Aulonocara baenschi benga, Dimidiochromis compressiceps, Sciaenochromis fryeri 'Iceberg', Pseudotropheus saulosi and Protomelas hertae. Nowadays the tank is running fine and a number of fish are displaying. The water quality is so good that we hardly get any algae on the rocks because the nitrates are really low.
If you would like to see the tank from close proximity feel free to pop in when you’re in the neighbourhood.
Photos by the authors except where otherwise indicated.
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