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Why Is Soft Water Bad for Pools?

By Ellen van der Wagt ; Updated September 21, 2017
Why Is Soft Water Bad for Pools?

The terms "soft water" and "hard water" describe the concentration of dissolved minerals in water. A low concentration of calcium, magnesium, iron and other elements results in soft water, whereas hard water contains more of these minerals.

Soft Water

Very soft water will attempt to balance itself by absorbing minerals until it becomes saturated. In the pool, the predominantly available mineral is calcium.


Soft pool water becomes corrosive and leaches available minerals. According to Poolcenter.com, soft water can damage the surface inside the pool by dissolving calcium from the plaster and tile grout. Soft water can also corrode metal fixtures and thereby causes metal stains on the walls and floor of the pool.

Determining Water Softness

In order to determine water softness, periodically measure the pH, alkalinity and calcium hardness of the pool water. Most home test kits have the necessary tools to analyze these properties. Pool stores provide a complimentary detailed analysis of a pool water sample.

Increasing Calcium Hardness

If the pool water is found to be too soft, water hardeners such as calcium chloride will increase water hardness.

Perfect Balance

A correct water balance is necessary to maintain the life of pool surfaces and pool equipment. It also ensures that the pool stays clean and hygienic.


About the Author


Based in southern California, Ellen van der Wagt has been freelance writing since 2009. Her articles appear on informational websites such as Answerbag, Trails, eHow, and Trazzler. She holds a nursing degree from Medical College in Germany and a master's degree in history from Pepperdine University.