How Do You Reduce Calcium Hardness in Pool Water?

Reduce the calcium content in a swimming pool by draining the pool of a percentage of its water, then refilling it with fresh or softened water, or add a calcium reducing chemical to the existing pool water. In pools with a proper chemical balance, calcium levels are between 150 and 400 parts per million.

Balancing the water in a swimming pool involves three major factors: pH, total alkalinity and hardness. Test a pool's hardness level by purchasing a pool testing strip, dipping the strip 18 inches below the water's surface and analyzing whether the results fall within normal hardness standards for pool water.

Excessive water hardness is a result of too much calcium and presents as cloudy water or a white-colored build-up on pool equipment and surfaces. It may be difficult to remove this scale without damaging concrete or copper surfaces.

If you have consistently hard water in your area, consider draining the pool annually or biannually to stave off reoccurring calcium build-up. Water hardness reducers aid in removing calcium from pool water by using binding the calcium with another chemical. This larger molecule is then removed by the pool's filtering system.

Buy and add pre-softened water to the pool, which helps bring the water back into balance. Caution is necessary in this activity as too much softening agent could bring the water out of balance and cause corrosive damage to certain surfaces.