Your swimming pool pump turns on, but it does not circulate water. This could be the result of only a handful of problems associated with the filter, including a clogged filter, a low water level or a pool line blockage. If the water is not circulating in your filter, a immediate remedy is needed because the filter can suffer permanent damage if it continues to run without circulating water.
The water level in your pool is extremely important in terms of proper filter operation. The filter is designed to operate with water, or else the motor can become damaged. Therefore, if the water level falls below the skimmer, either from swimmer overflow or evaporation, it must be replaced immediately. The water enters the filter system through the skimmer, and circulation will be nonexistent if the water is too low. Turn off your filter if this is the case, and raise the water level to at least the halfway mark of the skimmer's vertical height.
If you live in a windy climate or have the pool sitting beneath a tree, you already know that leaves in the pool are a persistent problem. If you neglect the pool, and leaves continue to fall on the water's surface, they eventually make their way into the skimmer basket, which causes a loss of circulation. Clean this basket out weekly to make sure this does not become a problem with pool filter circulation.
The more common symptom of no pool filter circulation besides the water level is a dirty and clogged filter system. As filters operate under normal conditions, they become dirty with the particles and small debris it has collected during normal operation. Backwashing your filter is necessary when the pressure gauge on the filter rises 8 to 10 pounds per square inch (psi) past its normal operating pressure. This same principle applies to all thee filter types: sand, diatomaceous earth or cartridge filters.
When you vacuum your pool to pick up dirt and debris that has settled to the pool bottom, you typically remove the skimmer basket. This is done in order to fit the vacuum attachment into the skimmer. Therefore, the basket that blocks this dirt is no longer there, but there's a second basket inside the pump itself where the large pieces of debris reside. This basket must be cleaned out as well because it will block pool filter circulation. This is especially true if you've recently vacuumed up small twig pieces and large leaves that blew into your pool after a storm.