The API Freshwater Hardness GH and KH Test Kit tests tap water and freshwater aquariums for general hardness (GH) and carbonate hardness (KH). Keeping these factors properly balanced creates a more healthy, natural environment for your freshwater aquarium fish.

The Freshwater Hardness GH and KH Test Kit helps detect stress on fish caused by rapid pH shifts, which result from low KH levels and helps aquarists duplicate the natural habitat of their fish.