API Carbonate Hardness KH Test - Fresh/Salt

(CARBONATE HARDNESS) Tests tap water and fresh or saltwater ponds & aquariums for carbonate hardness(KH), the measure of dissolved carbonate and bicarbonate ion concentrations, also called alkalinity. For fresh & salt water Helps detect stress on fish caused by rapid pH shifts, the result of low levels of KH Helps to maintain the correct buffering capacity in ponds & aquariums. 1 Bottle Kit.