Swimming Pool Chlorine: Does It Raise The pH Level?

by George
(New York)

Does swimming pool chlorine affect the pH level?

Adding an excess amount of chlorine increase the pH?

Some people only use a combination of muriatic acid and pool chlorine to maintain the swimming pool, but I guess that is due to the fact that they live in places where the water has alkaline components (also known as "hard water") so the acid "lowers" the pH.

Am I doing the right things?

Any help?

Thanks for the question George

Water systems and municipalities will have a different make-up of their water which differs from city to city.

Here in central Oregon the water company runs the water at a pH level of 7.8ppm - 8.2ppm and the alkalinity at 30.

This is due to the older homes with copper piping not being able to handle the lower pH levels, say 7.0ppm - 7.2ppm.

The water company dumps a tremendous amount of soda ash into the system, which raises the pH levels.

The only kind of pool chlorine that I know about that might raise your swimming pool pH level is calcium hypochlorite.

This swimming pool chlorine has a pH level of 12, so places with a higher pH level might be better served by using liquid chlorine called sodium hypochlorite.

Adjust Your Swimming Pool Chlorine

Calcium Hypochlorite

Sodium Hypochlorite

Hope this helps


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Stabilizer Low in Swim Spa

by Don
(Mountain Home, AR USA)

I have a 1200 gallon swim spa. I have used Pool Basics water balance conditioner once, which contains 100% Cyanuric acid. It did not raise the Stabilizer from the low reading. It did not effect the pH or Alkalinity or Chlorine readings, all remaining good.

I am using a Nexa salt chlorine system.

Can I add more Cyanuric Acid and keep trying to raise the Stabilizer?



Thanks for the question Don

I'd like to have your complete chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper). It makes troubleshooting much easier.

With readings of "good" it's difficult to say with any degree of certainty what the problem is.

How much CYA did you use in the spa? How long after you added the CYA did you take the test? What was your initial CYA reading and what was it after you added the CYA?

You always want to wait for one full turnover of the water before testing again and making another adjustment. For a 1200 gallon spa pulling 20 - 25 gallons per minute (GPM) you'll take another test after 1 hour.

Being that hot tubs are hotter than pools, the chlorine will be eaten up faster. A normal CYA for both pools and hot tubs are between 30 - 50ppm.

You can use Dichlor to get the chlorine and CYA in the spa. Be careful when using Dichlor as it can get out of hand quickly.

For every 10ppm of chlorine added with Dichlor, you'll raise the CYA by 9ppm.

For every 10ppm of chlorine added with Trichlor tabs you'll raise the CYA by 6ppm.

To post a reply, or if you have a similar question, you can see your post on the Q&A page in the "Cyanuric Acid (CYA)" category.

Check back to this post for updates or answers.

If you need immediate assistance (within 24 hrs) or for emergency personal assistance, you can make a donation of your choice and I'll answer your questions by phone.

Contact Me


Hope this helps and have a great Summer.


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