Leisure Time O Filter Clean Cartridge Cleaner Soak-and-rinse formula for cartridge, D.E. and sand filters Compatible with all sanitizers including bromine, chlorine, salt water, ozone, minerals and biguanide. For more than 25 years, Leisure Time has been the premier name in spa water care Removes oil, grease, dirt and soap Overnight soak will complete removal of all contaminants Great on filter cartridge and de filters This item is not for sale in Catalina Island