This Nature2® W22465B Swimpure Single Cartridge, 3'', 6/Pack contain minerals, such as silver and copper, that have long been known for their sanitizing antimicrobial properties. Nature2® brings the benefits of these safe elemental ingredients to create pool water that is noticeably cleaner, clearer, and softer. Replace your pool mineral cartridge every 6 months to keep your pool clean, clear, and algae-free. SwimPure Cartridge Filter Inserts reduces the need for chlorine by as much as 80% while maintaining safe algae-free water. With a reduction in chlorine or other sanitizers, comes the elimination of stinging eyes, dry skin and bleached swimsuits. The SwimPure canister slips inside Hayward's cartridge element.