Sensitive and accurate test for measuring dissolved or weakly chelated copper. The Salifert Copper Test Kit combines ease-of-use with laboratory-grade precision. Copper is often used in medications that treat for parasites. However, copper concentrations higher than therapeutic values can be toxic to fish. Copper is toxic to invertebrates and should not be present in reef aquariums. Use Salifert Copper Test Kit to detect copper or to measure residual copper levels before and after using copper cures in fish-only aquariums. Also great for testing tap or source water for copper. For marine and freshwater aquariums. 50 tests.