AZOO's KH test kit is suitable for freshwater and saltwater. Carbonate hardness is an indicator of the level of bicarbonate. It can be used for freshwater or saltwater where bicarbonate is an important buffer. Bicarbonate can be dissociated and become HCO3, CO3, CO2, H+, OH, etc. to stabilize the buffer system and maintain the pH value. KH will influence CO3 solubility and is also the source of biogenic decalcification for water plants.