Also Known As: Calcium build up

Scale is an unsightly mineral deposit that can build up on pool surfaces, accessories and equipment, typically at the water line. If left untreated, scale can become extremely rough, causing skin abrasions and damaging swimmers bathing suits.

In addition, scale is a major cause of pitting surfaces, which can result in premature damage and costly repairs. Preventing scale is the first line of defense.

These mineral deposits can come from a variety of sources. In some municipalities, well water could be the culprit. Chemical treatments can also leave these deposits and cause scale. Typically, the water’s calcium hardness, total alkalinity, total dissolved solids and pH tell whether or not scale is a possibility. This is one of many reasons it is important to test pool water frequently. When the water chemistry is balanced, scale is less likely to form. In water that is difficult to keep balanced, a sequestering agent can be added to prevent mineral deposits from forming.

Luckily, scale can be removed. If the water’s pH is high, getting it lowered can help break down the scale. A simple solution of one part muriatic acid to 10 parts water (adding the acid to the water, rather than the water to the acid) can encourage the scale to flake. For tougher scale problems, a brush or soft cloth can help. For really big scale problems, it may be necessary to employ sandpaper or a metal-wire brush, or even a belt-sander and a more concentrated muriatic acid solution.