Ultraviolet sterilizer suspended multiple filter. Stage one - mechanical: Advanced multi-layered polyfiber floss traps micro & macro organic particles and foreign debris. Stage two - chemical: Super-activated carbon granules absorbs many disolved contaminants, odor, impurities, and discoloration. Stage three - biological: Hi-flow bio-sponge promotes colonization of beneficial organisms essential to a healthy aquatic environment. Porous, biological sponge promotes beneficial organisms colonization. Stage four - biological: High efficiency UV germicidal lamp can effectively destroy the DNA of bacteria and organisms in the water to completely kill bacteria, which is a real green water killer.