Leisure Time Filter Cleaner This is a highly concentrated solution that cleans dirt, oil, grease and soap film from cartridge filters. This is enough solution to clean 110 square feet of filter area. For maximum effectiveness, soak overnight this will assure complete removal of all contaminants including those that may have been deeply set over months of use. Filters should be cleaned every three months or as needed. This product is compatible with chlorine, bromine and biguanide sanitizers.