Bio wheel technology provides biological filtration that is up to 10 times greater than regular power filters. Biological filtration is necessary to remove ammonia and nitrites from aquariums. Water is filtered through the porous sponge wheel before returning to the aquarium.Cartridges should be replaced each month. This replacement bio wheel is for use in the Aquatic Edge 6, 8, or 10 gallon Bowfront Glass Aquariums 790049 006 or 790049 010.