API GH / KH Test Kit
Quick, easy and accurately test your aquarium's hardness at home!
From the manufacturer:
When keeping freshwater fish and plants, the general hardness (GH) and carbonate hardness (KH) of aquarium water should match their natural habitat. The API® GH & KH TEST KIT helps you duplicate the natural habitat of your fish to prevent stress, keeping them healthy!
Contains 2 test bottles, easy-to-ready instructions, and glass test tubes.
Full instructions included in each test kit. Number of tests determined by hardness of water being tested. Use in conjunction with pH test kits!