Sometimes a marine aquarium is broken down as the aquarist no longer wishes to keep one and is to sell it. This is quite sad really but of course there’s more than one reason why this should happen. Sometimes though an aquarium needs to be broken down when the aquarist is still fully interested and doesn’t really wish to carry out such a drastic action.
Breaking an aquarium down means removing all the parts, cleaning and then reassembling them after removing dirt from below the rocks and any sand. As said, it’s a drastic action and causes considerable stress to the aquarium inhabitants and to the aquarist. The aquarium could be a reef type which has been running for years and is beautiful. Why on earth should it be broken down, why not let it continue?
Routine maintenance of an aquarium is accepted as essential. Without it the aquarium display will deteriorate and the inhabitants will eventually start to exhibit signs of stress, a major one being disease. In some aquariums dirt accumulates which cannot be dealt with without disturbing the overall display. We all recognize dirt which gathers in some areas where the seawater flow could be low and it also appears in sand. It also tends to appear beneath rocks. Normally the aquarist siphons it out when doing a routine seawater change and if there is more than one area to be serviced then each one is done in turn. This usually keeps things acceptable.
Unfortunately, there is a situation that could arise where this routine siphoning of dirt eventually is not enough. This is where dirt accumulates at the base of rocks, particularly where the rocks are numerous such as with a reef. The dirt appears there as seawater flow is much reduced. Siphoning cannot reach under the rocks. It becomes worse if there is a decorative sand bed or a deep sand bed (DSB) beneath the rocks. It is not recommended to have either type of sand bed beneath rocks. The reason for this is sand compaction and dirt accumulation. It is recommended that rocks are placed in first and sand applied afterwards if it is required. (Also rocks should never stand on sand as they could well be unstable.)
It is quite easy to avoid dirt appearing beneath the rock structure by building a simple cleansing system into the design. It can be retrofitted of course but this will cause disruption to the display. All that is required is some marine quality flexible and rigid tube, pipe fittings plus some aquarium silicone. The final item is some plastic ‘egg crate’, which is sold in sheets and is made up of joined together fairly small squares.
First of all the base area of the aquarium needs to be measured. The ‘egg crate’ should be sized to, say, 2” smaller than the visible edges, that is 2” away from the viewing glass sides. When this has been achieved, rigid plastic pipe (1/2” or so diameter) should be cut about 1 1/4” long. All the pieces should be of equal length. Enough of these should be cut to support the ‘egg crate’ at about 3 or 4” spacing all along the edges and on the inside. For each 3 ft of aquarium length ensure that there is space to lay across the width of the aquarium a length of rigid pipe. These cut supports should be put in position and filled with silicone, this is to ensure they do not fill up with dirt and also anchors them in position. When the silicone is set, which usually takes around 24 hours, the ‘egg crate’ can be placed on top, this should not be siliconed in place.
Now more rigid plastic pipe is required, again about ½” diameter. This will be used as outlets for seawater that will be pumped under the crate. For each 3 ft of aquarium length cut a piece of pipe 1” shorter than the width of the ‘egg crate’. At about 1 1/2” intervals drill 1/8” holes. There should be a level row of holes on one side of the pipe and on the exact other side and in line should be another row. One end of the pipe should be sealed off completely making sure the plug is firmly in place with silicone. So, for a 3ft length aquarium there should be one pipe, for a 6ft two etc. A 3ft aquarium will have the pipe positioned in the centre and across the width, with the holes positioned to send seawater horizontally across the base of the aquarium in two directions.
The ‘egg crate’ needs to be removed again, and the drilled pipe(s) put in position. Ensure the pipe is firmly in position so that it cannot move using silicone as needed. When the silicone has set connect a flexible pipe to it and run the pipe to the intended position of the pump. Ensure the flexible pipe is securely fixed to the rigid pipe and cannot come loose. Now the ‘egg crate’ can be put back in place, but not glued as rocks will keep it immobile.
If all silicone is cured rocks can be placed on the ‘egg crate’ and once they are stable and acceptable in appearance the aquarium can take seawater. Heaters, circulation pumps and other support equipment can be fitted and turned on as required.
The finishing job is to fit the powerhead which will drive seawater under the rocks through the drilled pipe(s). The location has already been decided and so the procedure is straightforward. The pump needs to be sized of course. A guide for each length of rigid drilled pipe of around 12 to 15” is to allow about 1000 litres per hour. I use a pump of this size and it operates adequately. It is a very good idea to use foam on the intake of the powerhead as this will stop dirt getting to and possibly blocking the rigid pipe outlet holes. This foam should be cleaned under a tap weekly.
The DIY involved in fitting such a plate to support the rocks is very easy and the materials not expensive. The time involved could be as low as a bit more than one day and this is mainly to give time for the silicone to set.
It’s obvious that if a DSB was to be incorporated in the main aquarium then this couldn’t be done. It’s best to have a DSB in a sump anyway. If a shallow decorative sand bed is required this is possible – fit an angled piece of plastic all around the open edges of the ‘egg crate’ to hold the sand back without spillage. The dimensions of the ‘egg crate’ could be adjusted to increase the sand bed width.
I removed a rock and took a not very good photo (above) showing the ‘egg crate’ in my aquarium. The photo at the head of the text shows some of my reef.
Pumping seawater under the rocks into a clear space has advantages. Oxygenated seawater enters the area and this also helps prevent temperature layering. The important advantage is in cleanliness as dirt is caught in the seawater movement and propelled away. My reef aquarium had the system built in from the start over 8 years ago and the bottom is nearly clear. There is a small accumulation of dirt at each end of the base furthest away from the outlet pipe but it’s not a problem. It’s certainly far better than having to break down the aquarium because the dirt problem had become unacceptable.