CupriSorb, 4 L / 1 gal. Powerful adsorbent of copper and heavy metals Will remove copper more rapidly and efficiently and is thus ideal for emergency copper removal Extracts all types of copper from water and if in continuous use, will remove copper from gravel or substrate as well Will allow maintenance of invertebrates in copper treated tanks by removing copper leaching from substrate 250 milliliters removes up to 7,500 milligrams of copper