Maintaining water balance in a swimming pool is essential to ensure that the water is clear, healthy and enjoyable. This balance is based on three fundamental parameters: pH, alkalinity (TAC) and hardness (TH). Well-balanced water extends the lifespan of your equipment, optimises the effectiveness of treatment products and offers impeccable bathing quality.
Here are some indicators to analyse to understand water quality :
Ideally, your pool water should have a pH level between 7 and 7.4 (for bromine treatment, the pH should be between 7.4 and 7.6). These are the optimal levels for water disinfection.
The TAC indicates the concentration of carbonate and bicarbonate ions. This measurement reflects the water’s ability to absorb fluctuations in pH and stabilise it. The unit of measurement for TAC is ppm (parts per million) or the French degree (°f), and it should ideally range between 80 and 150 mg/l. By adjusting the TAC level of your water (TAC+ or TAC-), you can carry out what is known as ‘buffering your water’.
Total hardness (TH) refers to the concentration of calcium or magnesium ions in water. It is measured in French degrees (°f) or in parts per million (ppm). The ideal TH level is between 10 and 20°f. The higher the TH, the harder and more calcareous the water becomes. Conversely, the lower the TH, the softer the water is.
Everything you need to know about water hardness.
Water temperature has a huge impact on these parameters. The warmer the pool water, the more the pH tends to rise naturally. Check your water balance more often during heatwaves!
Unbalanced swimming pool water should never be neglected: it's essential to intervene quickly to preserve bathing quality, the durability of equipment and the effectiveness of treatments.
In terms of comfort, water with unstable parameters can become irritating to the skin, eyes and mucous membranes. This can lead to redness, itching and general discomfort.
From a technical point of view, unbalanced water loses its ability to stabilise treatment products. As a result, you have to use more chlorine, pH+ or pH-, algaecides or anti-scale agents, which increases maintenance costs and complicates day-to-day management.
This chemical imbalance also has a direct impact on your system: it accelerates wear and tear on linings, weakens seals and damages equipment (pumps, filters, heat exchangers, etc.).
The Taylor scale is a standard tool in the swimming pool industry for quickly assessing the carbonate balance of the water
Using this data, it is possible to classify the water into one of the three states mentioned above. The aim is to achieve balanced water that is neither corrosive nor scale-forming, thereby ensuring greater equipment durability and optimal chemical stability.
La balance de Taylor se présente sous forme de diagramme.
Please note: this applies only if the water temperature is 24°C.
📌 Good to know: you can use a Taylor paper balance (printed cross-table), specialist software or mobile apps to carry out this reading quickly after your analyses.
The Langelier Saturation Index (LSI) is a calculation method used to determine whether the water in your pool is chemically balanced, corrosive or scaly.
The calculation is based on the formula: LSI=pH(measured)-pHs(theoretical)
The pHs is a reference value calculated from a number of parameters: water temperature, TAC, TH and dissolved solids (TDS).
This calculation is particularly useful for anticipating the appearance of problems linked to mineral imbalance in the water, such as premature wear and tear on installations or cloudy water that is difficult to treat.
📌Automatic Langelier index calculators are available online or integrated into certain electronic pool analysis kits.
To guarantee perfectly balanced water throughout the season, it's essential to monitor these parameters regularly using a suitable tester (test strips, electronic testers, colourimetric kits, connected water analysers, etc.).
The frequency of pH, TAC and TH analyses should be adapted to external factors, and your pool water should be monitored weekly during the summer season, or even daily in very hot weather or after storms or heavy rain.
If the slightest anomaly is detected - whether it's a pH that's too low, an unstable TAC or a TH that's too high - you need to take immediate action using the appropriate corrective products: pH+, pH-, alkalinity booster, hardness stabiliser, etc.
These parameters can be measured using a suitable testing device (test strips, electronic testers, colourimetric kits, connected water analysers, etc.).
Depending on the parameters analysed, regular and thorough water treatment is essential, particularly during busy periods. Disinfection (using chlorine, bromine, active oxygen, etc.) must be tailored to the water temperature, the number of bathers and the pool’s exposure.
Water filtration also plays a vital role in maintaining the quality of your pool water. In summer, the filtration time should be adjusted to suit the water temperature. The rule of thumb is: daily filtration time = water temperature divided by 2.
Everything you need to know about pool filtration
Cleaning the swimming pool requires a daily routine (for the water’s surface) and a weekly routine (for the bottom, walls, filter and skimmer baskets).
Of course, depending on the weather (wind, storms, Saharan dust storms), you may need to clean your pool more often.
Everything you need to know about weekly pool maintenance
For crystal-clear water and maximum bathing pleasure, water balance must never be neglected!
In short: testing, treating and filtering your water, and cleaning regularly, is the key to clear, healthy, enjoyable water all season long!