Blue Ribbon Polyester Filter Fiber (10 lb bulk) – A large box of soft, 100% polyester filter floss ideal for aquarium and pond filtration systems. This material can be packed into wet/dry filters, canister filters, power filters, or skimmers to trap debris and particulates, providing effective mechanical filtration. The polyester fiber is non-toxic and inert, safe for all freshwater and saltwater aquariums, and also offers surface area for beneficial bacteria growth helping keep your tank water crystal clear and healthy for fish.