Although they provide plenty of entertainment, swimming pools also require plenty of care and maintenance in order to keep them functioning properly. Aside from testing pool water's chemical levels, cleaning the pool and maintaining its water temperature, pool owners also need to care for pool filters correctly. How often you need to update or change a pool filter depends on whether you have a diatomaceous earth, sand or cartridge filter.
Diatomaceous Earth Filters
Diatomaceous earth (DE) filters are common in private, home pools and are not recommended for public pool use. They require cleaning via internal backwash every four to eight weeks. Each time the filter is backwashed, the DE needs to be replaced. New DE powder costs from $2 to $4 (in early 2011). DE filters should be deep cleaned at least once per year. A deep cleaning consists of draining the filter, removing the grid assembly and thoroughly rinsing it with water.
Cartridge filters require very little maintenance and are simple to care for and clean. To clean this kind of filter, you simply open the housing or case, remove the filter cartridge and rinse it. On average, a cartridge filter needs cleaning every six months and needs replacement every three to five years.
Sand filters use No. 20 silica sand to collect dirt, and they are actually more efficient once they start to trap debris. Although sand filters need to be back-washed every one to two weeks, the actual sand in the filter needs replacement only every six or seven years. Replacement sand costs from $50 to $100 (in early 2011). The entire filter unit lasts about 25 years, and even then may need replacement only because it is outdated and individual parts needed for repair are no longer available.
Public swimming pools typically have greater use than private swimming pools and must be cleaned much more frequently than private pools. More people using a pool means more dirt tracked into pool water that needs to be filtered out. Because of public pools' increased traffic, DE filters are not recommended for public pools. They filter at a much finer rate, fill with dirt very quickly and can clog easily. If you need to use a DE filter in a public pool, it should be cleaned every two to four weeks instead of the every four to eight weeks required for a private pool. If the water becomes very dirty, clean the filter up to four times per day until the water is clean. Use a sand filter for public pools because, as mentioned, they operate more efficiently once they trap dirt, they require much less maintenance than DE or cartridge filters and they do not need replacement often.