Also Known As:
Instead of a cartridge or DE filter, water flows through a layer of rough sand, which traps dirt and debris of at least 25 to 40 microns. When the sand loses its effectiveness, its easy to backwash the pool water, rather than replacing the sand or cleaning the filter. Sand can be replaced about every three to 10 years.
Like with cartridge and DE systems, a pump powers a sand filtration system. Water enters the tank through a diffuser and is then pulled into the bed of sand. As it passes through the sand, debris is left behind. The filtered water exits the bottom of the filter and is returned to the pool.
Compared to DE filters, sand requires more time to remove very fine particles. However its efficiency is comparable to a cartridge filter. Of course a sanitation system is also necessary to clean the water of bacteria and viruses. With a sand filtration system water should be backwashed about once a week and the filter should be chemically cleaned twice a season.