TetraPond Clear Choice Biofilter PF-1 For Efficient Filtration Easy out-of-pond accessibility and simple maintenance Mechanical pre-filter sponges remove suspended debris to improve water clarity Bio Ring media provide massive surface areas for beneficial aerobic bacteria Interchangeable .75" and 1" intake fittings Use with water gardens upto 1200 Gallons or with Koi ponds upto 500 Gallons Ships in Certified Frustration-Free Packaging