Swimming Pool Balance: Acceptable Water Chemistry Ranges

Balancing the water in your swimming pool is an important part of pool maintenance. To make the pool a safe and pleasant environment in which to swim, you need to ensure it has the right levels of chlorine, alkalinity and dissolved minerals.

Read on to learn how to keep track of the chemicals in your pool. Here is a quick guide to the acceptable ranges for various properties of your swimming pool water.


The pH of a swimming pool defines the acidity of the water. A pH of 7 means that the water is neutral, neither acidic or alkaline. Ideally, the water should be very slightly alkaline, which means that it should have a pH of slightly above 7. Some sources advise pool owners to keep the pH of their pool water between 7.2 and 7.8, while others recommend a tighter range of between 7.4 and 7.6.

You can measure pH using test strips, which are easy to use. All you need to do is dip the strip in the water and read the results according to the colour code provided by the test manufacturer.

Total Alkalinity

Alkalinity is closely related to pH. It is a measure of all the alkaline salts, including carbonates, bicarbonates and hydroxides that are present in the pool water. The higher the alkalinity, the more stable the pH of the water.

If the alkalinity in your pool is too low, you will probably struggle to keep the pH in the acceptable range, as it will be very sensitive to tiny changes in the water chemistry. If the alkalinity is too high, you will have difficulty changing the pH when you need to. Ideally, the total alkalinity of pool water should be between 80 ppm (parts per million) and 120 ppm.


Chlorine kills bacteria and keeps pool water safe and hygienic for swimming. However, too much chlorine can make pool water irritating to skin and eyes. Pool owners should test chlorine levels daily to ensure the pool is safe to use. The safe range is between 1.0 and 3.0 ppm.


Some pool owners use bromine instead of chlorine to keep their swimming pool water clean and safe. If you use bromine in your pool, then you should test daily and aim for a safe range of between 3.0 and 5.0 ppm.

Cyanuric Acid

Cyanuric acid is a chemical that pool owners use to keep chlorine levels stable. Cyanuric acid suppresses the activity of free chlorine in the pool, which means that you will need a higher chlorine level if your pool contains too much cyanuric acid.

If a test strip shows that the cyanuric acid level in your pool is too high (above 50 ppm) then you will need to drain off some pool water and add more water to dilute the level of this chemical. If the level is too low (below 30 ppm), you can simply add more cyanuric acid.

Calcium Hardness

Hard water contains calcium salts, which can lead to scaly deposits appearing on the sides of your pool. These deposits can damage your pump and filtration system. However, water that is too soft (contains too little calcium) can also be corrosive, as it leaches calcium from the sides of the pool.

Most sources recommend a calcium hardness level of between 180 ppm and 220 ppm, although some sources advise maintaining a higher range of between 200 ppm and 400 ppm.

For help maintaining balance in your pool, contact Shenton Pumps. We provide pumps that maintain a good flow of water through your pool, ensuring that all chemicals mix fully into the water.