Copper is often used as a treatment for parasite infested fish and it is essential that the correct concentration is used since high levels can be toxic to marine fish and invertebrates.
Tap water can also be naturally high in copper and it is therefore advisable to test for this on a regular basis.
The Salifert Copper Test Kit offers a very sensitive and accurate test for measuring dissolved or weakly chelated copper from 0.05mg/L to 2mg/L.
The kit can perform approx. 50 tests on tap or aquarium water as a routine check.