Water pH is a measure of acidity or alkalinity. The pH scale runs from 0 to 14, with 7 being neutral. Lower values are acidic, and higher values are alkaline. The acceptable range for spa water is 7-2 to 7-8, though many experts recommend an even narrower range of 7-4 to 7.6. Not coincidentally, this is the same pH range as that of human eyes one reason why a proper pH level is important for bather comfort.
When pH is low, the water is acidic. Acidic water can etch metals and plaster, stain plaster finishes, and cause bather discomfort, such as skin and eye irritation. Low pH also causes sanitizers to dissipate quickly.
When the pH is high, the water is alkaline, or scale producing. Alkaline water can be cloudy and form scale deposits on the spa surface and equipment. With high pH levels, sanitizers becomes less effective, and skin and eye irritation may occur.
Testing pH. The easiest way to monitor pH is with test strips, although more accurate results can be achieved with liquid test kits. With test strips, you simply dip or swirl the strip in the water according to the manufac-