When there is a decrease in the pressure from your jets, or when the pressure in your filter tank increases by 8 psi from when the filter was newly installed, it is time to clean your filters.
To clean the filter, first remove it from the canister and use a hose to wash away any debris between the pleats. Then soak the filter in commercially-prepared filter cleaner, or spray with the same to remove organic material and oils. In order to remove stains, soak overnight in a solution of one quart bleach and 5 gallons water. Thoroughly cleanse the cartridge with fresh water and reinstall it into the canister. Be sure to follow manufacturer's directions.
DO NOT use a high-pressure car wash wand, a stiff brush or acid wash to clean the filter cartridges as these methods can damage your filter.