Maintenance of a marine aquarium system, reef or fish only, is accepted as very important to its ongoing health. Water changes are done, filters cleaned and general observations of the interior made. Usually all is well, but sometimes occurrences arise which need dealing with.
For example, the aquarist may note that the output from a canister filter, used for bio or mechanical purposes, has dropped. This indicates that the media is in need of cleaning. Similarly, a powerhead used for circulation may have reduced output, or a return pump from a sump the same. It may even be that the device has stopped completely.
In the case of reduced flow the aquarist cleans the media or the pump intake mesh and no change occurs. In the case of a pump stopping completely, the aquarist may believe the pump has failed and start looking for a replacement.
True, there may be a problem with the pump itself. But before the decision to replace is finally made it is worth checking for calcareous deposits within the pump or tubing.
Calcareous deposits can form on the shaft of the pump impellor. This is the propeller like object that spins and drives the seawater. They are usually a thin shaft, around which at one end is a cylindrical ’bulb’ that is magnetised. At the other end is the propeller. On all pumps there is access to this object, which can be carefully withdrawn from its housing. When withdrawn it can be inspected, and it is usually obvious if deposits are causing difficulty for the device to spin. Turn it with the fingers – if it is stiff it needs cleaning, if it won’t turn cleaning will normally free it.
To clean, scrape the shaft with great care with a knife. Be very careful not to create additional grooves or indentations in the shaft. Deposits usually come off quite easily. When cleaned, test for spin again and, if all is well, re-assemble the device which can be re-started.
If the deposits are particularly resistant, then the impellor can be immersed in vinegar, as this will over time dissolve the deposits. This could take many hours in some cases, perhaps overnight or a day.
When this has all been done and the device re-started, it is possible that the flow rate has not increased. This can happen with some devices (such as canister filters) which move the seawater through tubes. In this case, the tube internal diameter needs to be checked. The check should be done initially at the point where the seawater leaves the powered device and enters the tube. Deposits may be found within the tube, and they can be poked and scraped clear. This should solve the problem.
Having done all of these checks it may be that flow rates are still lower than they should be, or the pump still doesn’t run. (To make sure there isn’t an electricity supply problem where a pump doesn’t run, try changing the fuse.) At this point the indications are that there is a fault with the pump. Check the impellor propeller blades – any broken or damaged? If so, a new impellor could be the answer. If not, then it looks like the pump unit needs replacing. Don’t forget the guarantee period if the device is fairly new.
Calcareous deposit problems can also be implicated in the often termed ‘old tank syndrome.’ This is where an aquarium system is getting on a bit in years, and the aquarist is not as keen as earlier on and doesn’t do maintenance and observations as well as in earlier days. The flow rates within the aquarium slow down, flow through a sump might be less etc. The corals are not as magnificent as they were. The system is, in other words, in decline. It could only be some attention to detail that is needed.
The problem of deposits on equipment is not widespread. It is probably more likely in hard seawater with its calcium etc content than in freshwater, so it is something to bear in mind. Check the efficiency of power heads and pumps during routine maintenance.
For safety, always disconnect an electrical device from the power supply before working on it.