CupriSorb" is a powerful adsorbent of copper and heavy metals. CupriSorb" will remove copper more rapidly and efficiently than carbon and is thus ideal for emergency copper removal. It extracts all types of copper from water and, if in continuous use, from the gravel/substrate bed as well. CupriSorb" will allow maintenance of invertebrates in copper-treated tanks by removing copper leaching from substrates. This product is sold by volume. Cited weight is minimal weight..