 The concentration of calcium in the reservoir was 14.87milligrams per litre from April 2001 to August 2006.During the same period, the concentration of calcium carbonate (CaCO3) was 57.73 milligrams per litre, slightly over Botswana's ideal concentration which means the water is hard.Also during the same period, the chloride concentration was 6.44 mg/l, the fluoride concentration was 0.54 mg/l, the potassium concentration was 6.72 mg/l, and the sodium concentration was 10.76 mg/l.