What is Total Alkalinity (TA)? Pool Maintenance 101

Total Alkalinity is an often misunderstood – and a bit confusing – topic when it comes to pool maintenance. Learn what total alkalinity is, how to calculate it, and what to do if it’s off.

What is Total Alkalinity?

Total Alkalinity, or TA, is the measure of the pool or spa water’s ability to resist changes in pH.  The TA acts as a buffer, or control, to keep the pH of your water at industry recommended levels.

Total Alkalinity and pH work closely together. Products and chemicals that affect TA also affect pH and vice versa. 

If the TA is too low (low alkalinity), the pH can “bounce” and this can adversely affect the water chemistry balance. This can lead to green water, stains on the floor and walls, and cloudy water. If the TA is too high, the pH can be difficult to adjust, leading to problems of its own.

How do You Calculate Total Alkalinity?

Testing for TA is relatively simple and can be done using test strips (much like testing for pH). You can also test with what is called a standard drop. This involves added one drop of reagent at a time until the color changes. The number of drops is multiplied by 10 to give you your TA number.

Many experts will tell you to test the TA regularly, but if you do a good job of maintaining your pool, it’s unlikely it will vary too much. We’d recommend weekly tests, but don’t stress if you miss a week.

What is the Ideal Total Alkalinity Level?

The industry recommended level for TA is 80-120 ppm (parts per million). 60ppm is too low,while 140ppm is too high.

After testing the water, if you discover that your water chemistry is out of balance, it is very important to adjust the TA first (with alkalinity increaser or pH decreaser), and then adjust the pH if necessary.  

Unbalanced alkalinity can lead to serious consequences that could possibly damage your pool.

Low Total Alkalinity can lead to:

• pH bounce
• Etching or staining of pool/spa surfaces
• Corrosion of metal parts in your pool or mechanical system
• Wrinkles in liner

High Total Alkalinity can lead to:

• Cloudy water
• Scale formation
• pH resistant to change/drifts upward
• High TA can be tough to bring down and may require you to add a pH decreaser in small increments over a 3-5 day period, retesting the level in one week’s time.

Keep up with your TA and be aware of how it can impact the pH of your pool. Keep your pool maintained, and don’t let too much time go by without testing.