Total Alkalinity (TA)

Total alkalinity is the measure of how stable the pH is. It measures the pool water’s buffering capacity to resist pH changes. Without control of the total alkalinity, the pH will rise and fall abruptly. The ability to resist this change in pH is due to the presence of carbonate ions and other compounds.

In general, total alkalinity should be kept between 80 ppm and 140 ppm but this will vary from region to region. Check with your local pool professional to see what the correct range is for your area. The ideal reading for alkalinity will vary due to three variables: (1) type of pool, (2) type of sanitizer, and (3) type of shock. Below are guidelines for each of these variables:

When alkalinity is either too high or too low, water acts much like that with a low pH or high pH level.

A low total alkalinity makes it difficult to maintain a desired pH and can lead to corrosive water, which can damage equipment. Green water can also be another symptom of low total alkalinity. To increase the alkalinity level, add sodium bicarbonate, typically packaged as “Alkalinity Increaser”, “Alkalinity Up”, or “Alkalinity Plus”. Always read the instructions on the label before adding any type of chemical, as manufacturers will recommend varying amounts to add per 10,000 gallons of water as well as the specific procedures.

High levels of total alkalinity can cause “pH lock”, which is when pH gets stuck and is difficult to change. High Total alkalinity can also cause cloudy water and scale forming. To decrease the alkalinity level, sodium bisulfate or muriatic acid can be added to the pool water – these are the same chemicals used to lower pH. Always read the instructions on the label before adding any type of chemical, as manufacturers will recommend varying amounts to add per 10,000 gallons of water as well as the specific procedures.

pH - Neutral, Low, High		Calcium Hardness