The three pack of Fluval FX4/FX5/FX6 Ammonia Remover Pads provides incredibly effective chemical filtration for freshwater and saltwater environments. The powerful, durable pads were designed to trap floating particles such as debris, waste or food, as well as reducing the amount of toxic ammonia found in your water. The Fluval FX4/FX5/FX6 Ammonia Remover Pad is great to use for preventing fish loss, outbreaks or dangerous spikes in ammonia as well as being ideal for as a post medication supplement for the aquarium and it's inhabitants. Dramatically increases filtration quality and efficiency in new or heavily stocked aquariums and can be replaced monthly or as required after water testing. Designed to be used with the Fluval FX high performance canister filter series.