6 Common Sand Filter Problems

A sand filter that fails to work sufficiently can make your pool appear to have no filter at all. By understanding the problems can arise, you will be in a better position to solve them quickly and ensure that you con continue to swim without problems.

Undersized Filter

Where you find that dirt and debris remains in the pool water after operation of the sand filter, you are likely to find that it is undersized for the volume of water in the pool and is insufficient to do the job. Replace the filter with one that is able to turnover the volume of water in the pool in 6 to 8 hours.

Sandy Pool

Where grains of sand escape from the filter and into the pool, it means that the filter contains broken, worn down or misaligned components. The backwash valve should be checked and replaced, if necessary, along with the body of the filter. It is also possible for large amounts of sand to be deposited in the pool if the laterals become damaged. These are the components which allow the water to flow back into the pool whilst keeping the sand out. Where this is the case, these need to be replaced before the sand is refilled. Make sure that the air tube has not suffered damage or been displaced; return it to its correct position to make sure that sand does not make its way back into the pool during the backwash process.

This could also be the result where the sand filter is too large and allows sand to pass through the valve during the backwash process.


A sand filter can become clogged where the incorrect sand is used. Sand particles that are of too fine a grade will clump together rather than allowing anything to filter through and is of such a soft consistency that that it will break down and clog the mechanism. Refer to the instruction manual and only use the type and size of sand that is recommended by the manufacturer.

Cloudy Water

The filter can appear not to be working if the water remains cloudy. Remember that the sand must be replaced and the filter cleaned on a regular basis to ensure that it continues to work at its optimum level.

Short Filter Cycle

A short filter cycle suggests that the filter is not doing an effective job because there is too much debris and sand clogging it. This stops the water from flowing properly. Clean the filter and replace the sand to rectify this problem.


When the filter has not been fitted correctly, a leaking sand filter can result. Examine the filter in accordance with the instruction manual to ensure that it is as it should be. Pay particular attention to the multiport valve and the gasket, which will need to be replaced if it is where the problem stems. Small fasteners that are not fitted properly, such as nuts, bolts and washers, can also be the cause of leaks. Solve this by ensuring that every aspect is securely fitted and that the tank itself has not sustained damage.