how much of total hardness is calcium hardness
Expected Levels. Total hardness in freshwater is usually in the range of 15 to 375 mg/L as CaCO3. Calcium. hardness in freshwater is in the range of 10 to 250 mg/L, often double that of magnesium. hardness (5 to 125 mg/L). Typical seawater has calcium hardness of 1000 mg/L, magnesium.