Fluval FX5/FX6 Fine Filter Pads help maintain clear water. This polishing pad traps tiny particles and debris in fresh and saltwater aquariums. Fluval Fine Filter Pads are uniquely designed to fit Fluval FX5 and FX6 High Performance Canister Filters. For freshwater and marine environments Bottom Media Basket Captures small particles Helps maintain clear water These polyester pads capture small particles and debris that can cloud water, and help maintain clear water. Fluval Fine Filter Pads should be used in conjunction with Fluval Water Polishing Pads to optimize the purity of aquarium water. For freshwater and marine environments.