API | GH & KH TEST KIT FOR WATER HARDNESS | FRESHWATER
Water Hardness is all about the mineral content dissolved in the water. These minerals originate from various sources but in high levels, they can bring white crusts to various locations around your aquarium. Water Hardness is measured in two forms: GH (General Hardness) and KH (Carbonate Hardness) and the appropriate levels of each depends on the species of fish your aquarium houses.
Specifically for freshwater fish, the API GH and KH Test Kit assesses just how prominent these minerals are in the water of your tank. This test kit is the best way to help duplicate the natural habitat of your fish.
PLEASE NOTE: KH can strongly influence pH. If you add a pH adjuster to your aquarium and the pH returns to its original level in a day or two, this is called pH rebound and it is caused by high KH.