Fluval U Underwater Filter BioMax, Replacement Filter Media, Fish Aquarium, A495

The Fluval U Underwater Filter BioMax is a reliable replacement aquarium filter media that helps keep the water in your tank clear. Although it doesn't come with a bag, it is not necessary and works effectively on its own. The 110 gram package, despite the misleading picture, provides enough media for your filtration needs. However, some customers have reported cloudy water until they replaced the previous biomax material and properly rinsed the stones before use. It is recommended to use two packs to fill up the Fluval U4, but only replace half at a time if replacing older Biomax material.