Quick elimination of all kinds of cloudiness in freshwater and marine water aquariums and in pond water: reusable foam for use in the filter Easy to use: cut the foam to the size you need (suitable for all filters). Layer as filter stage for pre- and long-term filtering Crystal-clear water: filters off floating algae and cloudiness. Offers a large surface for the settling of cleansing bacteria No release of harmful substances     water neutral fine foam with 30 ppi pore size Contents: 1 washable foam filter mat for aquariums (50x50 cm) for all types of filter  available in 2.5 cm, 5 cm and 10 cm thicknes