Calcium is important to the water balance in your pool. Low calcium will cause long-term damage to plaster, vinyl liners, grout in between tiles, metal rails, and even concrete decking around the pool. High calcium will cause scaling. Proper calcium levels also help to prevent foaming.
Normal Calcium Hardness levels in a pool are 200-400 ppm.
Dissolve in water before being added to the pool and should be applied to deep end of pool, or around the pool in above grounds, with pump running for minimum of 4 hours. If granules collect on bottom of pool, simply brush to disperse.