Water parameters

The fundamental qualities of swimming pool water are as follows:

Stabilized chlorine

• The water must be clear
• Water must be disinfected (curative action)
• The water must be disinfectant (preventive action: persistence)
• The water must be non-aggressive
• The water must be non-scaling

These essential qualities will be obtained through 3 complementary actions:

• Physical treatment: this is provided by your filtration unit.
• Chemical treatment: it allows you to regulate the parameters of your pool water and keep it healthy and balanced.
• Control of water parameters: analysis and correction.

Water is a living environment in perpetual evolution.

Your pool water must be analyzed regularly (at least once a week) since its parameters vary depending on the water temperature , surrounding pollution and the number of bathers.

The first action is to know and adjust the water balance which depends on 3 parameters:

The pH

The pH or hydrogen potential is related to the concentration of H+ ions, which represent the acidity of the water. The pH scale ranges from 0 (very acidic environment: high concentration of H+ ions) to 14 (very basic environment: low concentration of H+ ions).

A neutral pH is equivalent to 7. In a swimming pool, the ideal pH is between 7 and 7.2.

Water alkalinity: TAC

The bicarbonate and carbonate content is measured by the TAC (Total Alkalimetric Title). The unit of measurement for this parameter is °F (French degree) or ppm (parts per million) or mg/l.

Note: 1°F = 10 ppm = 10 mg/l

To ensure sufficient buffering capacity of pool water (buffering capacity is its ability to absorb both upward and downward pH fluctuations), the TAC value must be between 10 and 30 °F. If the alkalinity is too low, the pH will fluctuate greatly, while if it is high, it will be difficult to bring the pH back into its normal treatment range.

Water hardness: TH

The measurement of water hardness is called Hydrotimetric Title or TH. Like TAC, the unit of measurement for this parameter is °F (French degree).
Water hardness depends on its calcium and magnesium ion content. In swimming pools, the ideal TH value is considered to be between 10°F and 20°F.

Water that is too soft < 10°F is corrosive
Water that is too hard > 20°F causes scaling

Water is said to be balanced when the measured pH corresponds to the equilibrium pH (For a given TH and TAC, there is an equilibrium pH).

There are several methods for determining the equilibrium pH. One method is to use the Taylor balance diagram, which represents the calcium (limestone) carbonic (bicarbonate) equilibrium of water at a given water temperature of 24°C.

This simplified water balance diagram determines the equilibrium pH from a TAC and TH measured in the pool. If the pH measured in the pool does not correspond to the equilibrium pH, it is advisable to get closer to it by adjusting the TAC or TH. As you will have understood, measuring the pH of your pool water and correcting it are essential actions to have balanced water.

Do you have any doubts about your water balance? Then visit your local store for a free, comprehensive analysis.