Aquatic Arts FilterPlus Bio-Media Aquarium Filter Professional grade Bio Media for home aquariums; used in all of our holding tanks at Aquatic Arts Completely natural; contains no chemicals or artificial materials; will not alter PH or hardness Never needs to be replaced; instant and significant upgrade to almost any aquarium filter Enables higher stocking levels and greatly superior Bio Filtration to Bio Balls or Ceramic Rings Capable of housing anaerobic bacteria, which can greatly reduce the need for water changes