Reason for Draining Pool Filters

Changing Sand

• Sand pool filters require new sand about every four to five years, depending on the usage of the pool. Public pools with heavy usage need the sand changed every year, while private pools will usually go up to five years without needing the sand changed. When the pool pump continually has a high pressure reading over the clean reading and backwashing doesn't help lower the pressure, it is time to change the sand. Sand filters use #20 silica sand.

Winterizing

• During fall, the pool filter and pool are shut down for the winter. After removing some of the water from the pool, the pump drain is opened to allow the water to drain out of the pump. If the water is left in the pool filter, the water will freeze and cause damage to the pump. The drain cap is left off the drain outlet for at least one day to allow all the water to drain.

Broken Parts

• Sand filters have laterals inside the pump that are surrounded by sand. If the lateral is broken, the water must be drained and the sand removed from the pump to replace the lateral. There are some signs that can help determine if a lateral is broken, but one sign could be sand channeling back into the pool water.

Changing Grits and Cartridges

• The DE (Diatomaceous earth) filter will need to be drained if the DE grid must be changed because it has become frayed or torn. The cartridge pool filter system must be drained when the cartridge is replaced, which is once a year or longer. If the pleated cartridge is in good condition when the pool and pump are winterized, the filter can be reused the following season. However, if cartridge stops trapping small dirt particles and the pool water continually becomes cloudy, the pump should be drained and the cartridge replaced.