This API Nitra-Zorb Pouch is the perfect addition to your aquarium's filtration system. Designed for tanks up to 55 gallons in capacity, this filter pouch is ideal for keeping your freshwater aquarium clean and healthy. The pouch is made by API, a trusted brand in the pet supplies industry, and is specifically designed for use with aquariums and fish tanks. The filter pouch is easy to install and use, and is perfect for removing nitrate and other harmful substances from your aquarium's water. With its sturdy construction and high-quality materials, this API Nitra-Zorb Pouch is sure to provide you with clean and healthy water for years to come.