For Freshwater : General (GH) & Carbonate (KH) HardnessThe general hardness (GH) and carbonate hardness (KH) of aquarium water should match that of the natural habitat of the fish. Otherwise, fish will be stressed and prone to disease.
For Freshwater & Saltwater : Carbonate HardnessThe carbonate hardness (KH) of aquarium water should be tested frequently, since water with a low KH is subject to rapid shifts in pH, greatly stressing fish and making them vunerable to disease.
All fish thrive at a particular pH level. pH can fluctuate due to fish waste, tap water and build-up of natural acids. This kit allows you to easily and accurately measure the pH level and maintain a healthy aquarium for your fish. For Freshwater use Tests p H 6.0 - 7.6 250 tests