JBL Phosex UltraFilter material for the removal of phosphate from aquarium water. Key Features: Removal of phosphate from aquariums: filter material for the use in aquarium filters. To use: fill filter material into universal bag and place it in the aquarium. Insoluble iron compound; no release of any substances into the water. For fresh and saltwater: 340g for the permanent binding of 18,000mg phosphate.