API FILTRATION FOAM 20PPI pad is designed to fit API FILSTAR XP canister filters. Its thickness is ideal to filter large waste particles. Maintenance Every month wash the foam pad thoroughly in a basin of water taken from the aquarium. Never replace all filtration foam pads simultaneously so as to ensure optimum biological balance. Instructions Place a foam pad into the bottom filtration compartment below a 30ppi foam pad. Use as directed on product label. With API Aquarium products its easy to keep a beautiful saltwater freshwater or reef aquarium. For over 50 years API has been creating innovative research-driven solutions that make it easier to care for your fish and aquarium. API Aquarium Treatment Supplies are designed to work in conjunction with each other to provide best results to control algae promote healthy bacterial growth and help control and fish diseases and conditions such as ich and fin rot. They work to provide a safe hospitable environment for fish such as tropical community fish cichlids goldfish and more. With API you can spend more time admiring your fish and less time scrubbing your tank. Make sure to use all products as directed in order to ensure the best results.