Increases the Calcium Hardness level in spa & hot tub water. Water which is low in calcium can corrode equipment,
etch concrete and grouted surface, and provide an environment favourable to algal growth. The Calcium Hardness level of a spa and hot tub
should always be maintained between 200 and 275 ppm for concrete and tiled spas and hot tubs, and between 175 and 225 ppm for other
surfaces. Use a test kit to measure Calcium Hardness.