Hagen Fluval Edge Foam Pad and BioMax Renewal Kit, 3PACK Specially priced 3-PACK Each PACK includes a Foam Pad: Traps particles and debris from the aquarium for a healthy and clean environment Each PACK includes BioMax: Provides optimal colonization of beneficial bacteria and enhances the reduction of fish wastes, resulting in a healthier aquarium environment Both the Fluval Edge BioMax and the Fluval Edge Foam should be replaced every three months