What is Total Alkalinity? – Pool Care

POSTED Nov 17, 2020

Total Alkalinity (TA) is a very important component of overall water balance. Its primary role is to help keep pH in proper balance. The best definition of TA is; “the measure of water’s ability to resist a change in pH.” In other words, once you balance your pH successfully within the range of 7.4 – 7.6, it is TA that helps you keep it there. The secondary role of TA is to assist in providing the overall mineral content that all water requires to prevent unnecessary damage to surfaces. Water low in TA will see the pH bouncing up and down, almost uncontrollably. The swimming pool surfaces will also be at risk of long-term damage due to corrosion, especially vinyl liners. Water high in TA will find the pH constantly high and in need of reducing and a greater risk of scale formation, cloudy water and shorter filter runs.

Ideal TA Levels: 
Vinyl, Fiberglass, Paint, Synthetic Surfaces: 125 – 150 ppm. If a salt pool; 100 – 125 ppm.
Plaster (Marcite), Fully-Tiled, Aggregate: 80 – 125 ppm
Reducing Total Alkalinity

When TA is high, it requires lowering with Dazzle pH Minus, a safe, dry form of acid or Pristiva Acid Enhance, a safe, liquid form of acid. AquaAce, our highly accurate computerized water analysis program, will calculate the quantity of Dazzle pH Minus or Pristiva Acid Enhance required, dividing the total amount into equal applications over a number of days. Each application is designed to lower the TA by 10 ppm. Why do we only lower 10 ppm per application? Primarily to allow the lowering to be done in a controlled, predictable manner. The goal is to lower the TA without dramatically lowering the pH to damaging levels. If too much product is added, it is too difficult to control the pH. We can control pH when we control the rate at which the TA is reduced. It also proves to be a safer approach since we are dealing with acids. When done properly, the TA slowly steps down and the pH never drops below 7.2. Safe and Simple!

  1. Test pH – if above 7.2, apply that days application of Dazzle pH Minus or Pristiva Acid Enhance.
  2. If below 7.2, wait for the pH to climb above 7.2 before making your next application. Do not add Dazzle pH Plus to raise the pH back up. That will defeat what you are trying to do. Just leave it alone. It will come back up on its own.
  3. Apply by broadcasting evenly over the water surface, primarily in the deep end. Do not concentrate the product in one area. That will not get you where you want to go any faster or with any less product. 
  4. Make note of the application to ensure you complete the number of applications required.
If Your TA is Very High and You Wish To Speed Up the Process: 
  1. Test pH – if above 7.2, apply that days application of Dazzle pH Minus or Pristiva Acid Enhance. Filter continuously. After 2 – 3 hours, test pH again. If the pH is still above 7.2, apply another application of Dazzle pH Minus or Pristiva Acid Enhance.
  2. Repeat this process every 2 – 3 hours, making applications of Dazzle pH Minus or Pristiva Acid Enhance, provided the pH remains above 7.2. This process allows for many applications to be made per day, provided the pH remains above 7.2.
  3. Stop applications once the pH drops below 7.2, restarting once the pH climbs above 7.2 again.
  4. Make note of each application and stop once the total number of applications have been made, as per the AquaAce prescription.

Note: At the outset of this process, the pH is likely to be high, allowing many applications to be made each day. As the TA is reduced and gets closer to the desired level, the pH will start dropping and fewer additions will be able to be made each day.