Instructions For Using Filter Cleanse Cartridge Filters and Removable Diatomaceous Filter Elements– remove cartridge or elements and place in a suitable container with a solution of 1 lb. per 5 gallons of water. Soak for at least 4 hours, preferably overnight. Remove element from solution, rinse thoroughly and replace in filter. Sand Filters– backwash filter, then drain. Close drain valve and prepare solution, 1 lb. per 5 gallons of water. Add sufficient solution to cover sand. Allow to soak overnight (12) hours. Backwash until water runs clean and return filter to normal operation. How Much Product Do I Need To Clean The DeFender? Filter Cleanse - Soak Time 12 Hours Model Number LBS. of Filter Cleanse SP-18-48-175 SP-24-42-327 26 SP-27-48-487 32 SP-22-48-732 50 SP-41-48-1038 88 SP-49-48-1548 SP-55-48-2076