Oase Biosmart Gravity Pond Filter Pond Filters - Black - Up To 5000 Gal

• Multi-stage mechanical and biological filtration system in a compact package
• Designed for medium ponds or for ponds moderate biological load
• Biological filtration stage - water is channeled through a series of foam filters that allow settling of beneficial bacteria
• Harmful ammonia and nitrites are converted to nitrates which support plant life in the pond
• Features a built-in cleaning mechanism that does not require removal of the filter foams during maintenance.