Seachem CupriSorb 500ml is a narrow spectrum, synthetic adsorbent based filter material for removing copper and heavy metals from either freshwater or marine water. It extracts all types of copper, including chelated copper, and remains effective until it turns a deep blue-black color. It may be regenerated repeatedly. If placed in continuous service, it will gradually extract even precipitated copper and make invertebrate culture possible in tanks previously heavily treated with copper. Seachem CupriSorb is a powerful copper specific chelating resin.