Quick elimination of turbidity in freshwater and seawater aquariums and ponds: reusable filter foam. Simple to use: cut the foam individually (suitable for all filters). Insert at the filtering level for pre-filtration or long-term filtration. Clear and transparent water: filtration of floating algae and turbidity. Very large surface area for the colonization of cleaning bacteria. Does not release any toxic substances - fine foam, water-inert, 30 ppi porosity. Included: 1 washable filter foam sheet measuring 50x50 cm for all types of filters, available in thicknesses of 2.5 cm, 5 cm, and 10 cm.