Understanding Calcium HardnessFor Your Pool Or Spa
Calcium is naturally present in water.
Soft water has low calcium hardness and hard water has high calcium hardness.
Water used in the home is often deliberately softened because soft water is nicer for bathing and cooking, it launders clothes better, and it makes appliances like dishwashers and hot water heaters last longer.
However, some hardness is very desirable in pool and spa water. The ideal range for calcium hardness in pools is 200–400 ppm; a little lower in spas, 150–250 ppm.
A hardness treatment is inexpensive and a much better alternative. Warning to spa owners – bypass your water softener when you fill your spa.
If the water lacks calcium hardness, it becomes aggressive and tries to obtain more by dissolving it from plaster, concrete, grout, and other contact sources. On the other hand, a high level of hardness tends to create water scaling
The only way to lower high CH is by draining some and replenishing it with water of lower CH.