Consistent High pH

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J

JPhresh

0
Dec 21, 2014
24
Clayton, CA
I seem to be having trouble with keeping my pH in the 7.4 to 7.6 range... I've been adding about 30 to 50 ounces of dry acid every three weeks or so to keep the pH from going over 8. Is that normal? And what might be driving it up? Could the Pebble Tec finish be causing it? All of my other parameters have been nice and stable ever since I did the water change out (to address a high CYA problem I inherited from the previous owner) over two months ago. Here are the most recent readings:

FC 3
CC 0
pH 7.8
TA 90
CH 225
CYA 60
Temp 58F

Thoughts?
 
Yes, I'm guessing your fill water TA is fairly high?

Have you considered using liquid MA (Muriatic Acid) instead? It's advisable, because it's more economical and your dry acid is like adding Sulphates.

Lastly, that isn't much acid addition to be honest with you.
 
Regardless of the cause, I would do what it takes to keep my pH below 8.0 at all times

Is there a reason you are using dry acid over muriatic?

How long has this been happening? Your pool is over 2 years old at least, right?
 
Do you have any water features / spa?
Do you have a SWG?
Both of those can drive the pH up.
Plaster < 1 year old can as well ... does not sound like the case here.
Also the colder water will tend to drive the pH up.

How are you chlorinating?
Your TA is a little higher than we might suggest, the pH would not rise as fast if it was lower.

I recommend you start using muriatic acid so you are not building up sulphates in the water by using the dry acid.
 
Typical dry acid is a bit weaker, and the cost gets you. It would be a slow build at your rate, but it's still best not to build up Sulphates in the pool. One part of our philosophy is minimizing side effects, and dry acid falls in that category.
 
As you add acid, your TA will usually drop, unless you're adding a lot of high TA fill water. If you're adding bicarb to raise the TA back up, that will cause the ph to continue to rise. The pH rises some on addition of the bicarb and then it rises more over time as the high level of bicarb in the water converts into carbon dioxide and off gasses.

Try keeping your TA at about 60 and the pH at about 7.7 to 7.8.
 
Wow -- thanks for all the responses! I will definitely switch over to muriatic acid. I was using dry acid because I inherited a large supply, but that's pretty much gone now. I'm chlorinating using liquid chlorine (10%).

Otherwise, I don't think I have any of the conditions suggested above that might cause higher pH. The pool was installed long ago and the last refinish was done over five years ago. No water features. Not sure what a SWG is, though!

I tested my tap water before I did the change-out and the TA is 90, which matches what I now have in the pool, of course. Sounds like the TA will drop as I add acid, but if there's something else I can/should do to bring down the TA, please advise!

Otherwise, it seems my chemistry is behaving normally and I just need to stay the course of monitoring and adjusting pH as needed.
 

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elwood58 said:
Add enough liquid acid to drop your pH down to 7.2. Aerate your pool back up to 7.6 pH. Rinse and repeat. Your TA will drop nicely.
Click to expand...
You only need to do this if you are actively trying to lower the TA. In this case with a TA of 90ppm, I would just maintain the pH in the 7s and let the TA do as it will.
 
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