For many of us, the term pH brings back distant memories of school science lessons. But, for pool owners, getting the pH right in your swimming pool needs to be a top pool maintenance priority. In a nutshell, pH is a measure of how acidic or basic a solution is on a scale from 0 to 14. If the pH of a solution is below 7, it is an acid, while a pH reading above 7 is a base or an alkaline. For your swimming pool, the ideal pH range is between 7.2 and 7.6, with 7.4 being the perfect balance.

If the water in your swimming pool is clear, does the pH even matter? It most certainly does and here’s why.


Why do I need to test the pH of my swimming pool?


When your pool pH is low, meaning that it is too acidic, you are likely to see some nasty side effects, not only for your pool, but for swimmers too. A pool that is too acidic will end up causing serious corrosion to your pool equipment and metal surfaces, such as the pump, filter system, ladders, screws and pool lights. This damage may even extend to the plaster, tiles and cement of your pool surfaces. While swimming pool damage is one thing, your swimmers are hardly going to be having fun in acidic water. If the pH in your pool is too low, the water will sting eyes and nasal passages, while also causing itchy, dry skin. However, when your pool pH is high, meaning it is too alkaline, this can also result in a whole host of problems. You will likely find yourself making more trips to your local pool store to buy chlorine, as alkaline water largely inactivates the effectiveness of chlorine. Not only is your water therefore not clean enough, but as the pH increases, minerals come out of solution, which is exactly when pool water turns cloudy. Alkaline water also results in scale forming on pool equipment and surfaces, while swimmers suffer too, as a high pH can cause skin rashes and eye irritation.


How do I test the pH of my swimming pool?


Let’s get down to the practicalities. Testing the pH of your pool, fortunately, isn’t rocket science and is actually quite a neat trick to learn. A pH test strip is a cheap and easy way to test your pool water. Simply follow the instructions provided, although it’ll entail dipping the strip in your pool water for a set amount of time and then comparing the colour of the strip after removing it from the water to a colour chart. This will give you an indication of how acidic or basic your water is. Alternatively, you may want to purchase a digital pH tester, which will give you a numerical pH reading, but these require batteries, which will need to be replaced from time to time, and they may also need occasional re-calibration.

If you have time, patience and a little extra money to spend on your pool, a liquid pH test kit is the best way to get a good understanding of the balance of your pool water. Kits differ and you will need to follow the instructions carefully, but generally it will involve using a sample of your pool water and applying a reagent to this water, in order to test the pH level. Some kits go a step further and assist with the treatment of your water if there is an issue with the pH.


How do I change the pH of my swimming pool water?


If your pH is off, don’t fear, there is always a solution. For low pH values below 7.2, simply buy a pH increaser and pop this into your water. Baking soda can also be used, although this isn’t as effective and can result in a total alkalinity level that is too high. On the other hand, if your pH is too high, at a level above 7.6, just add pH minus to your pool. In severe circumstances, you may require a stronger acid, such as hydrochloric acid or sulphuric acid.

Balancing your pH as part of your pool maintenance routine takes time, but is an essential element in keeping your pool healthy and swimmers happy. If you need a little extra assistance from a pool professional, don’t hesitate to find a Pool Xpert near you and we’ll help get your pool’s pH balance back.