Fluval Ammonia Remover is a natural ion-exchange media designed to remove toxic ammonia as water passes over it. Controlling ammonia levels reduces stress on fish.Use this product to provide a healthy environment when setting up a new aquarium or maintaining one that contains a higher than average fish stock. Ammonia Remover gradually becomes inactive. Replace regularly, at least once a month. Reduces sudden unacceptable levels of ammonia, such as build-up of ammonia resulting from the removal of chloramine from municipally treated tap water For freshwater use only. Premium select media for use in Fluval Canister Filters, ideal for all filters. (3x180g in filter bags) Suggested Media Placement 105, 205, 305, 405: Mid, or Lower Level Media Baskets FX5: Top or Middle Media Baskets