API Freshwater Hardness GH & KH Test KitThe 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. General and carbonate hardness test kit Monitor GH and KH to create a more natural habitat For freshwater aquariums The Freshwater Hardness GH and KH Test Kit helps detect stress on fish caused