Deep Blue Professional phosphate remover cut to fit media pad traps micro and macro organic particles, foreign debris and excess fish food. For use in custom sumps/refugiums, hang-on filters, prefilter boxes and more. Safe for both freshwater and marine aquaria. Chemical and mechanical dual stage filtration. Rapidly reduces phosphate levels. Promotes a healthy aquatic environment. New thicker, more rigid design for extended use. Measures 18-inch length by 10-inch width.