Pool Magic+PHOSfree is ideal to treat your pool at the beginning and end of each season as well as reducing phosphates at any time as the first step of Natural Chemistry's Clear, Perfect Water Program. Pool Magic+PHOSfree contains all natural enzymes that break down non-living organics to make opening and closing fast and easy. A quick clean up to start off the season and to prevent non-living organic staining and phosphate build-up.