A powerful combination of Activated Carbon and Ammonia Remover, the AquaClear 50 Zeo-Carb Filter Insert effectively eliminates odors, discoloration and impurities in freshwater aquariums. This potent chemical duo prevents the buildup of toxic ammonia and nitrite, producing clean and healthy aquarium water. Exclusively designed for the AquaClear 50 Power Filter. Single pack. Net Weight: 90 g (3.1 oz)