Complex formula contains wetting agents, surfactants, cleaning compounds and release agents. Quickly loosens and removes oils, combined organic matters, calcium deposits and biguinide polymer material. Can be used as a backwash or as a soak cleaner. Compatible with ALL types of sanitizers and filter types. Sand Filter Cleaning: Add directly into the filter media, let soak for 4 hours or longer. After soaking, start pump with filter in the backwash position. Cartridge and DE filters cleaning: Add 16 ounces of Filter Clean to 2.5 gallons of fresh water. Remove media from filter and soak in solution for 30 minutes or longer. Remove and rinse.