Review on 🐠 Enhance Aquarium Water Quality with Fluval U Underwater Filter BioMax - A495 Replacement Filter Media by Maria Ward

The Fluval U4 does not come with enough ceramic media, so it's a good idea to get an extra one if you're going to buy one. A box is more than enough to fill a cartridge and it seems to be of better quality than mine despite being the same brand. The ceramic media comes in a mesh/mesh bag which needs to be cut open for use in the U4 or can be used in other types of filters entirely. Its pleasant filler, porosity and pieces are almost the perfect size and shape for medium sized filters. I have used it in several different filters both loose and in bags.