At AquaCave, we offer some of the best selection & best prices on aquarium water quality monitors, testers, controllers , and accessories for you marine, reef, and freshwater aquarium. Taking the time to test your aquarium water whether it is a freshwater or saltwater tank system is a very important part of maintenance, as it gives you an analysis of the condition or quality of the environment your tank inhabitants are living in. By testing the basic water parameters and various chemical elements such as ammonia, nitrate, nitrate, pH and other testable parameters regularly, you stay on top of what is happening in your system at all times. It also helps you diagnose any potential problem that may be arising, which allows you to prevent it from advancing or taking hold in the first place. From pH and ORP meters and controllers, dissolved oxygen testers and refractometers to professional quality meters and colorimeters, you'll find it here at the great price.