Salifert test kits are the epitome of accuracy and precision. Their wide range of available tests have all been designed to detect the smallest traces of certain elements, without interference from other chemicals within the water. Simply put, these are the best test kits you can buy- hands down. The sharp, contrasting color changes make results easy to read so there's no second guessing. Trust your aquarium to Salifert. This copper test will detect the smallest fluctuations of copper in saltwater aquariums so you can be sure your copper levels are correct.