Designed to control ammonia, nitrites, and nitrates, purfiltrum is a macro-porous synthetic polymer that removes soluble and insoluble organic impurities. By removing nitrogenous waste that can be converted into unwanted, harmful chemicals, you are encouraging a healthy, safe environment for your aquatic inhabitants. Polishing water to unparalleled clarity, you will be amazed with the level of performance purfiltrum has to offer! What makes it even better is it is completely regenerable, simply follow the directions on the packaging.