JUWEL Carbon Sponges absorb odour compounds and turbidity as well as toxic compounds in your aquarium, leaving the water crystal clear. The fact that active charcoal in the form of a sponge is used guarantees even flow conditions for the filter medium, creating a very large and therefore highly effective surface. Due to these characteristics JUWEL charcoal filters are also perfect for filtering out residual medication after treating your fish. Characteristics of the JUWEL Carbon Sponges Absorbs odour compounds and turbidity as well as toxic compounds Ensures crystal-clear water Filters out residual medication Suitable for use in freshwater and saltwater aquariums