The M25 Single Cartridge can be used for pools up to 25,000 gallons. Nature2® uses the power of natural minerals to give you cleaner, clearer water while providing peace of mind with round the clock algae control, even when your pump is not running. Utilizing EPA-registered technology, Nature2® is a conveniently simple solution, made with minerals like silver and copper, that safely and effortlessly sanitizes water while reducing your chemical usage by up to 50% in most pool. You won’t feel, smell, or be affected by heavy chlorine usage. Additionally, lower chemical use helps keep pH in a neutral range and prolongs the life of your equipment for lowered maintenance so you can just enjoy your pool.