PONDMASTER CLEARGUARD PRESSURIZED POND FILTER keeps your pond fresh and clean with dual-action biological and mechanical filtration. Clearguard's unique design filters with beneficial bacteria using bio-media while at the same time, mechanically polishing water with a reusable filter pad. This system can be added to any pond and will effectively lower ammonia and nitrite levels in the water. With the available UV Clarifier installed, Clearguard controls green water in the pond while its multi-function valve selector easily clicks into place for convenient filtering, backwashing, rinsing and winterizing.