The Fluval AquaClear Freshwater Ammonia Remover Insert for AC20/AC30 Aquarium Power Filter are ammonia-absorbing media inserts for AquaClear 20 and 30 filters. This chemical media is formulated to pull toxic ammonia from the water, ideal for new aquariums or emergency ammonia spikes. By controlling ammonia and nitrite, it helps prevent fish stress and keeps the aquarium water safe and healthy. Each insert fits perfectly in the filter basket, providing continuous protection against ammonia buildup. Available in Singular and 3-Pack Option