Fluval replacement parts are exclusively designed for Fluval Chi Aquariums. Choose from Filter pad and Foam pad. Filter Pads: Fluval Chi Filter Pad has two sides that combine to provide thorough and effective mechanical and chemical filtration. Custom-sized, it fits perfectly inside the filter chamber to prevent debris bypass. The polyester side filters out debris and contaminants. The carbon side filters out harmful liquid substances, colorants and odors for a healthy and clean environment. This replacement filter is exclusively designed for Fluval Chi Aquariums. Foam Pads: Fluval Chi Foam Pad captures excess particles and debris, plus it supports the growth of nitrifying bacteria for a healthy and clean environment. This replacement pad is exclusively for Fluval Chi aquariums. Replace foam pad every 2-3 months to help maintain a clean and healthy aquarium.