Total alkalinity is one of the most important things to test for in your pool water. The total alkalinity is a measure of how much alkaline substances there are in the water with a normal range being between 80 and 120 ppm (parts per million). The total alkalinity relates to the pH levels in your water, and if an adjustment needs to be made to the pH and alkalinity, you always want to balance the alkalinity first.
When the total alkalinity is within this range it prevents rapid pH changes and stabilizes the pH level. If the total alkalinity is too low gunite and plaster walls can become etched, metals corrode, the pool walls and floor can stain, the water can turn green, eyes burn and you can have pH bounce (pH rapidly going up and down randomly). If the total alkalinity is too high the pH is difficult to adjust, the water becomes cloudy, the pool constantly needs acid (according to your test kit) and the chlorine loses its efficiency as a disinfectant.
We recommend you test the total alkalinity regularly once per week during peak use in the summer with your test strips, and with a monthly water test at your local pool store. Total alkalinity should change very little in a well-maintained pool. To raise the total alkalinity you can use sodium bicarbonate, alkalinity or ph Up. To lower the total alkalinity you can use muriatic acid or ph minus (a powder form of acid).
Remember, lowering the total alkalinity is a slow process and when you’re adding the acid, we recommend adding it while the filter is on by pouring it into the pool next to a return line allowing it to easily mix into the pool. The acid should only be added a little at a time waiting 2-4 hours between applications. If the alkalinity is very high it could take days or even weeks to reduce.
Here is a table to help you determine how to properly change the total alkalinity in 10,000 gallons of water.
Increase Total Alkalinity 10 PPM
Sodium Bicarbonate (Baking Soda) 1.4 pounds
Sodium Carbonate (Soda Ash) 14 ounces
Decrease Total Alkalinity 10 PPM
Muriatic Acid (Hydrochloric Acid) 2/3 qt. or 26.0 fl.oz.
Sodium Bisulfate (Dry Acid) 2.1 pounds