Tout savoir sur l’alcalinité de l’eau (TAC)

L’alcalinité de l’eau, aussi connue sous le nom de TAC (Titre Alcalimétrique Complet) est un élément essentiel à l’équilibre de l’eau, avec le pH et le TH (dureté de l’eau). Un bon équilibre de l’alcalinité de l’eau détermine le pouvoir « tampon » de l’eau et impacte la stabilité du pH et l’acidité de l’eau.

The TAC regulation and stability are therefore very important, which should be checked regularly to keep the water healthy and clear.  If you encounter a pH problem, measure the TAC first and then the TH. This can save you the extensive and unnecessary use of chemicals.

What are the TAC targets?

The TAC should be between 100 and 200 mg/liter depending on the treatment used in your pool or spa. At the beginning of the season it should ideally be between 100 and 150 mg/l.

what are the consequences of a too low or too high TAC ?

  • Lorsque l’alcalinité de l’eau est trop basse (<à 100 mg/l), il n’y a pas d’effet “tampon”. Le PH fait le yoyo. Ainsi, le pH, responsable de la désinfection de l’eau, n’agit plus et les mesures sont très instables. L’eau devient irritante pour la peau et les yeux et agressive pour les équipements. L’eau se dégrade alors rapidement.
  • Conversely, with an alcohol content that is too high (>to 250 mg/l), the water becomes cloudy and limescale deposits appear. Your equipment can then be damaged

Comment mesurer l’alcalinité de l’eau ?

L’alcalinité de l’eau se mesure avec des bandelettes colorimétriques ou avec des testeurs électroniques (photomètres), utilisés par les professionnels.

Other devices like  ICO Pool and ICO SPA measure TDS (Total Dissolved Solids in Water) which includes carbonate and bicarbonate concentration (TAC). All about TDS, TH and TAC.

TAC in your pool

  • In the spring , during the restart, the TAC is high due to water renewal (passive overwintering) and can reach 220 mg/l. En suivant les advices to restart your pool on spring , the TAC should drop back down naturally within a few days.
  • In summer, check the alkalinity level (or TDS) once a month.
  • In the fall, a lower TAC tolerance ( between 80 and 100 mg/l) can be tolerated.
ICO Pool measures the alkalinity level of your pool with its TDS probe.

TAC in your spa

  • During each quarterly draining, the TAC will naturally increase (up to 220 mg/l) and then naturally stabilize with the activation of the filtration. 
  • Check the alkalinity rate (or TDS) once a month.  
ICO spa measures the alkalinity level of your spa water.

Comment modifier le taux d’alcalinité ?

  • To increase alkalinity : You can use baking soda or sodium carbonate. Refer to the product label for the dosage.
  • To decrease alkalinity: If the TAC is slightly high, filtration to oxygenate the water for several hours may be sufficient to correct the problem. For high TAC, sodium bisulfate should be used. These products are very strong, so wait 24 to 48 hours before swimming..
  • To get a good water balance, TAC and TH are crucial to achieve a pH balance, which acts effectively in the disinfection of water. all about pH