PH irelevant with cya in water?

[jokael]

I have always heard that the pH-level is important for the chlorine to work best. Here at TFP I also hear that the pH should be lowered before slamming, in order to give the chlorine the best environment.
But then someone showed me this article that says, than when cya is present the pH can be ignored.

Chlorine, pH and Cyanuric Acid Relationships

pH controls chlorine strength (% HOCl), but NOT when Cyanuric Acid (CYA) is in the pool. CYA takes over control of chlorine strength. Did you know that? Chlorine and cyanuric acid.

blog.orendatech.com

Is that correct?

 

[Bperry]

I have always heard that the pH-level is important for the chlorine to work best. Here at TFP I also hear that the pH should be lowered before slamming, in order to give the chlorine the best environment.
But then someone showed me this article that says, than when cya is present the pH can be ignored.

Chlorine, pH and Cyanuric Acid Relationships

pH controls chlorine strength (% HOCl), but NOT when Cyanuric Acid (CYA) is in the pool. CYA takes over control of chlorine strength. Did you know that? Chlorine and cyanuric acid.

blog.orendatech.com

Is that correct?

No, it’s not correct.

Before a SLAM, the pH is lowered because the pH test isn’t reliable when the chlorine levels are over 10ppm. And the pH tends to rise over time so this helps keep the pH on the 7’s during a SLAM. It’s not for any kind of best environment.

I have back up to note that the article doesn’t say pH can be ignored. It just says that lower pH allows chlorine to do its job better when there is no CYA in the water but pH is still important for all other reasons that pH is used for like CSI/LSI. pH cannot be ignored.

 

[DrewLG]

when cya is present the pH can be ignored .... Is that correct?

Kinda. With CYA in the water, pH has practically no effect on the HOCl concentration. But you still need to monitor pH for other reasons: bather comfort, plaster longevity, water cloudiness, etc.

 

[JamesW]

The effect of pH on the effectiveness of chlorine is mostly overrated and overemphasized.

If you are following the “Industry Standards” of a maximum of 4 ppm of FC, then the pH might be more important.

However, using the higher levels that are based on the FC/CYA ratio, the FC should be adequate for all pH levels that you will find in a pool.