The most important chemical measure of your swimming pool is the pH. This is a measure of the relative acidity of your swimming pool water. It is measured on a scale of 0 (strong acid) to 14 (strong base), with 7 being neutral.
For swimming pools, the ideal pH is 7.4 to 7.6, which has a slight alkalinity. This allows the water to be comfortable to the human eye while maintaining water that is not corrosive or scale forming. If the pH of the water falls too low (below 7), the water becomes acidic, which irritates eyes, etches plaster walls, corrodes metal fittings and stains walls. If the pH of the water gets too high (above 8), then scales can form on the pool walls, chlorine becomes inefficient, water becomes cloudy and eyes become irritated.
Your swimming pool should come with the necessary materials to test pH which is an easy process. Chemicals are available at retailers which can raise the pH in swimming pools. If your pH level is too high, your local retailer can recommend a PH reducer to lower pH levels.
For a detailed resource on swimming pool water chemistry, visit the North Carolina Department of Environmental Health Web site: http://www.deh.enr.state.nc.us/ehs/quality/wph.htm.