What is the ideal pH of the water in a swimming pool? How to calculate and maintain it?

Variable according to many elements, the pH is a swimming pool water quality indicator which must therefore be monitored very regularly using colorimetric testers or a pH meter. If it is too high or too low, it is essential to perform a adjustment in order to avoid problems. Let’s take stock of this famous potential hydrogenand see together what it is essential to do if its value is too low or too high.

What is pH?

The Hydrogen potential of swimming pool water (abbreviated as pH) is none other than the measure allowing the concentration of the hydrogen ion to be expressed. This is how we check thealkalinity or theacidity of a solution. The pH is measured using a graduation scale ranging from 0 to 14. The lower the value, the higher the acidity and the higher the value, the stronger the alkalinity (also known as basicity). And pH neutral is therefore at 7, the concentration of acids and bases being equivalent.

Swimming pool water, neutral pH imperative

The ideal pH of the water in a swimming pool must be between 7.2 and 7.4 some swimming pool specialists speaking of an ideal rate of 7.4. You can swim in neutral, slightly basic water. If it is not within this range, it affects the water balance and its quality because the very quality of the treatments is conditioned by the Hydrogen potential, whether it is too low or too high.

It should be noted that certain factors can have an impact on this Hydrogen potential, in particular:

  • The treatment products that we use in the swimming pool, knowing that chlorine, for example, interferes with the pH and causes an imbalance in the water, an interference with which we are less confronted if we resort to a saline treatment.
  • The lime content water which varies by region. it’s about the Water hardness which is expressed in TH (Hydrotimetric Title).
  • L’rainwaterwhich causes a drop in the pH of swimming pool water because in certain geographical areas it can be very acidic with a pH between 5 and 6.
  • The temperaturei.e. the higher it is, the more the pH increases,
  • The pool attendance rate : the more people there are in the pool, the higher the pH of the water.

Vigilance is therefore essential from the start-up of the pool until its wintering.

Checking the pool’s pH: the best solutions

As soon as the pH is no longer stabilized, many problems are to be deplored, namely:

  • The ineffectiveness of treatment products,
  • The water becomes irritating to the skin and eyes of pool users,
  • algae grow,
  • The water can turn green, even brown,
  • The limestone deposits on the filters, the coating, the walls and eventually deteriorates them.

Pour to protect yourself against all these risks, it is crucial to check the pH level at least once a week, but it can be even more frequent if there are many bathers or if storms are raging, for example. To perform a reliable reading, you can use:

  • Of the colorimetric pH testers which can be tablets or strips: their use requires great attention because the results are quickly distorted. These testers indicate pH by means of a color code.
  • And pH meter : it is an electronic device to be inserted into the water which then displays – reliably – the results on its screen.

If after checking it is found that the pH is unbalanced, it is imperative to correct it without waiting.

Correct a pool water pH when it is out of balance

Two products make it possible to carry out a readjustment in order to find an ideal pH and therefore, pool water of very good quality. It’s about :

  • of a pH raiser in granules, powder or tablets, which are called pH Plus product (or pH+): it must be used when the Hydrogen potential of the pool water is below 7.2.
  • And pH reducer called pH Minus (or pH-): it is necessary to use it as soon as the Hydrogen potential of the swimming pool water is higher than 7.4.

It is essential to follow the instructions supplied with each of these products to the letter. It is recommended to let them act for a few hours before carrying out a new pH check and, if necessary, making small readjustments.

Finally, it is possible to install a pH probe the cost of which varies between 60 and 300 €. This device is able to independently readjust the pH of the pool and automatically as soon as it detects an imbalance. Thus there is no longer any need to resort to correctors (Plus or Minus) and handling of products is avoided.

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