Ideal range: 7.4 – 7.6 ppm


A scale of measurement, pH was invented to measure the acidity of water in the brewing of beer in the early 1900s. pH stands for potens hydrogen, Latin for “hydrogen power,” as acidity is caused by a predominance of the chemical species H+ or hydrogen ion.





pH is measured on a scale from 0 – 14, with a pH of 7 being neutral. Below 7, the water is acidic and above, the water is alkaline (“basic”). The pH scale is logarithmic, meaning that every whole unit increase is 10 times its predecessor. Therefore, a pH of 6 is 10 times more acidic than a pH of 7 and a pH of 3 is 10,000 times more acidic than a pH of 7!

Note that the pH range recommended for pool/spa waters is slightly alkaline, which promotes bather comfort, as the pH of the human eye is about 7.5.

Problems caused by Low pH:
Problems caused by Hi pH:
  • corrosive water
  • pitting of concrete
  • metals dissolve
  • surface staining
  • scaling water
  • white film/crusty deposits
  • plugged filters
  • reduced circulation
  • cloudy pool
Non-Balance Problems
  • chlorine loss
  • vinyl wrinkles
  • skin/eye irritation
Non-Balanced Problems
  • chlorine inefficiency
  • skin/eye irritation