Brilliance® Spa Calcium Hardness Increaser for Hot Tubs and Spas -14 ozBrilliance for Spas
Brilliance Calcium Hardness Increaser raises spa water to the recommended level of calcium hardness.
All water contains some natural hardness and it varies by geographic region. Calcium Hardness is the amount of dissolved calcium in your spa water. It is important to maintain the correct level of calcium hardness. High levels of calcium can erode pumps and cause damage to the internal workings of your spa.
Watch that you don't get your calcium hardness TOO high as there is no product to decrease the level of calcium hardness!