What is the ideal range for calcium hardness in pool water?

The ideal range for calcium hardness in pool water is 200 to 400 ppm (parts per million). This range is essential for several reasons related to the overall health and maintenance of pool water. Calcium hardness helps to prevent issues such as corrosion of metal equipment and surfaces, which can lead to costly repairs and equipment failure. If calcium levels are too low, water can become aggressive, corroding pool plumbing, ladders, and heaters. Conversely, if the calcium hardness is too high, it can lead to scaling on the pool surfaces and equipment, cloudy water, and problems with filtration.

Maintaining water within the 200 to 400 ppm range provides enough calcium to ensure the protective qualities of the water while minimizing potential negative impacts. This level supports the stability of pH and total alkalinity, contributing to the overall balance of the pool water chemistry, which is critical for swimmer comfort and safety.