Aquarium filter sponge is 100% polyester material suitable for filtering in aquarium with all kinds of water, product is resizable. larger surface for denitrifying bacterial to grow, which is proper for fish. clean up once every month, effectively improves water and dramatically reduces fish-dying rate. it can be washed and reused. This product is suitable for sea water, fresh water, water tanks, the size can be cut freely. According to the analysis of the experts, products with this pore gap and flexibility and the most suitable breeding grounds for cultivating the fine nitro bacteria