About this product range:~ Foam 20
- (20 ppi
- pores per inch) &8226; Removes coarse debris & solid wastes before they enter chemical & biological filtration chambers. &8226; Can be rinsed & re-used many times &8226; Open-cell design permits free flow of water DIRECTIONS FOR USE IN RENA Fil Star Filters: 1. Place Foam 20 in the lowest part of the bottom basket in the Fil Star Canister Power Filter. 2. Rinse Foam 20 thoroughly under running water every 2 to 4 weeks, or as needed to maintain good flow through the filter. 3. Replace after several months use to maintain efficient filtration in the aquarium.