Carbonate hardness, (KH), is a measure of bicarbonate & carbonate content of the water. Carbonate hardness contributes to pH stability and can also act as a Dioxide of Carbonate backup reserve if it falls too low.
Carbonate is derived from potassium bicarbonate. It increases both carbonate hardness and potassium. The concentration of carbonate is 2,000 meq/L (5.600 dKH). In addition, it contains 78,300 mg/L potassium.