Review on Fish Water Quality API Test Kit by Jasmine Baker

In the lower right corner of this field is written FOR FRESHWATER ONLY. If you only have seawater, ONLY buy the KH kit. Just not this one. Only buy one if you have both a freshwater tank and a seawater tank. Both tests work with fresh water. Only KH works for salt water. GH is NOT required for salt water. Make sure the kit includes a color bar to compare readings. I was missing. KH = Carbonate Hardness (testing the alkalinity (buffering capacity) of the water - testing in salt water GH = Total Water Hardness - not required in salt water. Carbonate Hardness (KH or CH) refers to the water's ability to maintain a stable environment and therefore the health of the fish. Carbonate Hardness is the "buffering ability" of water.) General Hardness (GH) refers to the "hardness" of water caused by calcium and magnesium ions. Different aquatic species prefer different environments, some prefer "hard" water and some prefer "soft" water. The hardness of your water is often determined by the source of the water.