pH Correction

To keep the chlorine working it is recommended that the pH is kept below 7.6. However if pool water becomes less alkaline it also gets more corrosive and less comfortable to swim in. Also, if pH drops below 7.2 it will start to attack some liners. Therefore, the pH is recommended to be above 7.2. So the normal range that a pool water should be kept at is 7.2 to 7.6 (ideally 7.4 to 7.6). On most pools the pH will tend to rise so pH minus (sodium bisulphate ) is added. The exception to this is if trichloro isocyanuric acid is being used in which case the pH will go down and an alkalinity builder will be required. The pH is tested using pH test kit which uses phenol red tablets in a comparitor tube.

It is difficult to predict how much acid will be required to reduce the pH to a precise level as it depends on what else the water contains. For instance a soft water will require less acid to adjust the pH than a hard water. We suggest adding 500 grams for every 45 cubic meters (10,000 gallons) and then re testing after 12 hours and redose if necessary. You will soon become familiar with the amount your particular water requires. To dose dissolve in warm water in a clean plastic container and distribute evenly around the pool with the filter operating.