Does liquid stabilizer also increase total alkalinity?

Calgone18

Member
May 20, 2020
6
Sharon, MA
I added a gallon bottle of liquid stabilizer to my pool because it was at 14. I have a salt water pool so have quite a ways to go. I noticed that it increased my Cyanuric acid which is great but my total alkalinity also increased about 10 points too. I don’t want to overshoot my total alkalinity with this stuff. You guys ever hear of Cyanuric acid in liquid form also raising total alkalinity?
 

mknauss

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May 3, 2014
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Laughlin, NV
Cyanuric acid will raise total alkalinity. It is cyanurate alkalinity. The remainder is primarily carbonate alkalinity. If you take approximately 1/3 of your CYA level, that is what the portion of total alkalinity is cyanurate alkalinity.

Poolmath handles that for any calculations that TA is used for.
 

JamesW

TFP Expert
Mar 2, 2011
19,723
Normal cyanuric acid won't change the TA because it's a weak acid.

When you add it to water, some of the hydrogen ions dissociate and lower the pH.

C3H3N3O3 --> C3H2N3O3- + H+

Cyanuric acid --> cyanurate + hydrogen ion.

The cyanurate counts toward the TA and the hydrogen ion subtracts from the TA by the same amount.

The amount that becomes cyanurate depends on the pH.

1÷(1+10^(6.88 – pH)) = % cyanurate.

pH........% cyanurate
7.2............68
7.4............77
7.6............84
7.8............89

Liquid stabilizer is sodium cyanurate. At a pH of 7.8, 11 percent will become cyanuric acid.

100NaC3H2N3O3 + 11H2O --> 89C3H2N3O3- + 11C3H3N3O3 +11OH- + 100Na+

The hydroxide ion raises the pH and TA some. The cyanuric acid doesn't count towards the TA, but the remaining cyanurate does contribute to the TA.
 
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Calgone18

Member
May 20, 2020
6
Sharon, MA
Thanks yeah it could just be a coincidence that I noticed that TA went up to 75 from 68 when I added the gallon. I’m at 24 right now for Cyanuric acid and want to get up to the recommended level of 60. I just didn’t want to overshoot the TA by adding the stabilizer. Based on your explanation, I should be fine. I’ll cautiously add and measure in small increments to be sure though. You think it would make a difference if I use liquid salt stabilizer versus Cyanuric acid granules?
 

JamesW

TFP Expert
Mar 2, 2011
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The liquid stabilizer does raise the TA some, but it's not a big deal.

I would add whatever you have or whatever is more convenient.
 
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JamesW

TFP Expert
Mar 2, 2011
19,723
When adding liquid stabilizer, every 2.58 ppm of CYA results in an increase of 1 ppm TA.

To go from 14 to 60 ppm CYA using liquid stabilizer, the TA will increase by 17.8.

(60 - 14) ÷ 2.58 = 17.8 ppm.
 

JamesW

TFP Expert
Mar 2, 2011
19,723
The best TA is whatever makes the pH stable.

If the pH is constantly going too high, the TA is too high.

If the pH is constantly going too low, the TA is too low.

When the pH is stable for long periods of time, the TA is right.

In other words, don't worry about trying to achieve a predetermined number.

Adjust as needed to stabilize the pH.
 

mknauss

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May 3, 2014
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TA can be 50 to ?? Depends on your water, scaling tendencies, etc. Typically whatever TA keeps your pH steady, if possible.
 

JamesW

TFP Expert
Mar 2, 2011
19,723
The carbonate alkalinity is the portion of the TA (Total Alkalinity) that affects pH rise.

The carbonate alkalinity is also called the adjusted alkalinity.

The adjusted alkalinity is the TA - (CYA x cf).

Cf is the correction factor, which is based on the pH.

pH........CF
7.0.......0.22
7.1.......0.24
7.2.......0.26
7.3.......0.28
7.4.......0.30
7.5.......0.32
7.6.......0.33
7.7.......0.34
7.8.......0.35
7.9.......0.36

For example, if the pH = 7.6, TA = 90 and CYA = 70, the adjusted alkalinity is 90 - (70 x 0.33) = 67.

So, a pool with a TA of 67 and no CYA will be about as stable as a pool with a TA of 90 and 70 CYA.

Since most of the new alkalinity was cyanurate alkalinity, the pH should be about as stable as before you added the liquid stabilizer.
 

duraleigh

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I noticed that TA went up to 75 from 68 when I added the gallon
That's part of the problem. There is no test available that will test CYA or TA that accurately. Increments of 10 ppm is the best you can do on both.