Designed specifically for fx series canister filters, ammonia remover pads offer both effective mechanical and chemical media in a convenient, space-saving format.. Features. Specifically designed for fluval fx series filters. Effective at reducing and controlling toxic ammonia spikes. Effectively traps floating particles for clear water debris, excess food and waste . Ideal for new and heavily stocked aquariums. Use after medicating fish. Custom fit to increase filtration efficiency. For best results, replace monthly or as required after testing water. Convenient 3-pack format. For use in freshwater and saltwater aquariums