JBL Blue fine mesh filter foam 50-50-5cmFast turbidity removal in freshwater and saltwater aquariums and ponds: reusable filter foam.Easy to use: cut foam individually (fits all filters). Clear water: filtration of floating algae and turbidity. No toxic emissions - fine, water-inert foam, 30 ppi porosity.1 washable 50x50 cm filter foam plate for all filter types, available in thicknesses of 2.5 cm, 5 cm and 10 cm.