Copper is often used to treat many parasitic infections on fresh and saltwater fish. To be effective; the copper concentration in the aquarium must be maintained at the therapeutic level for several weeks. Frequent testing is required to monitor the copper level in the aquarium. Some fish species are very sensitive to copper treatments; therefore; follow the copper treatment manufacturer's directions carefully. Copper should not be used or evident in aquariums with invertebrates; including snails; shrimp; crayfish and corals; as well as in freshwater or ponds with plants. Tap water may contain copper leached from pipes and ultimately; it can accumulate in the aquarium. This kit does 90 tests and can be used in freshwater and saltwater aquariums. Kit contains: a dropper bottle for accurate dispensing of test solutions; easy to read instructions and a color chart; a non-staining glass test tube with snap-tight cap. Range is as follows for fresh and salt water: 0.25 PPM; 0.5 PPM; 1.0 PPM; 2.0 PPM; 4.0 PPM.