Pool Chlorine levels and pH


Pool Chlorine levels

Pool Chlorine Levels are important because all swimming pools need sanitisers to disinfect the water. If left untreated water-borne organisms can breed, which can contaminate the water, making it unsafe to swim in. In addition, low disinfection/pool chlorine levels can result in algae growth, resulting in unsightly green blooms on the water surface.  

Chlorine levels need to be regulated and monitored to ensure that the right amount of sanitiser is added to your swimming pool.

Too little Chlorine in a swimming pool can result in the following:

  • Bacterial growth
  • Waterborne Illness
  • Cloudy Water
  • Algae growth

However, too much Chlorine can result in the following:

  • Eye, nose and skin irritation


pH is a measure of the acidity of the water. The pH scale runs from 0 to 14, where pH 7 is neutral. If the pH of the pool is above 7, the water is basic; if it is below 7 the water is acid. The optimum pH range for pool water is about 7.2 to 7.6.  

A Low pH gives:

  • Aggressive water, which damages the mechanical components of the pool
  • Irritations of the eyes and mucous membranes
  • Damage to the pool liner

A High pH gives:

  • Poorer chlorine disinfection
  • Skin irritation
  • Lime precipitation
  • Cloudiness


Therefore, it is crucial that your swimming pool is tested regularly for both pH and Chlorine.

Pool Gem measure three key parameters in water: pH, which is a measurement of the acidity of the water; ORP, which is a measure of the effectiveness of the sanitizer; and temperature of the water.

In addition, Pool Gem can measure the level of phosphates in the water. A high level of phosphates, in water can result in algae growth and high chlorine consumption.

For more information contact us.