pH Testing

The pH of water is a measure of how acidic or alkaline it is. The pH is measured using a scale from 1–14, where pH 1 is very acidic, and pH 14 is very alkaline. The acidity of the water is a measure of the amount of hydrogen ions present in the water.

The pH of the water will affect the chemistry of the water and how it reacts with chemicals and surroundings, and so in the majority of applications, maintaining a stable pH is essential.

  • Drinking water – pH is important to monitor and control in drinking water as it can directly affect the performance of the treatment and disinfection process. It is also monitored downstream as it can affect pipework corrosion, plumbosolvency, taste, etc.
  • Surface/groundwater – Most forms of aquatic life are sensitive to the pH of their environment. Even small changes in pH can have negative consequences. pH will also affect other important equilibriums such as the proportion of ammoniacal nitrogen existing in the toxic NH3 form in bodies of water.
  • Wastewater – pH of waste waters is controlled to protect the environment, but also the equipment from corrosion. pH of discharged waters will also affect the receiving source and must also be considered.
  • Pool and spa – pH is a fundamental parameter in pool and spa testing.  Maintaining the right pH, ensures the correct form of chlorine in the pool and helps protect against corrosion.
  • Soil, irrigation and hydroponics – soil and hydroponic pH is a critical parameter for healthy plant growth and crop yield. It is also used to calculate lime requirement for neutralising soil acidity.
Testing Your Hot Tub and Spa
Spa Chemistry Guide
Introducing the Pooltest 4 Photometer