Reducing Persistently High pH

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wjmano

Gold Supporter
May 19, 2021
62
Wildwood, FL
After managing my newly constructed pool for a year, all my chemistry is quite stable with minimal effort on my part. Much of my success can certainly be attributed to TPF members and this forum.

My only issue is a persistent rise in pH. I find that it wants stabilize at around 8.3. Have been adding muriatic acid consistently (at least weekly) using enough to theoretically reduce my pH from the usual 8.3 down to 7.2. Like clockwork, if I test a few days later it’s heads to 8.0 quite quickly and then tends to level off around 8.3. All this occurs while maintaining TA in the range of 60-70 without much trouble.

My question is whether I should (a) continue what I’m doing, (b) just let the pH remain relatively high at around 8.3 or (c) do something else like trying borates which I know little about.

Thanks in advance for any help.

Bill
 
Bill,

Looking back at your logs looks like you may be running TA too high. As Marty recommended quit adding baking soda and let TA drift down to 60 or even below. I ran about 50 ppm with no problem and it stabilized the pH. We never let the pH get over 8.0. I kept it around 7.7 and tried to avoid higher than 7.9. Eventually I went to borates and that helped tremendously. I think it also just took way more time for my pool to cure than most. After several years I was down to adding acid about once per month with borates. When you get the pH back in range of TFP recommendations you'll see your CSI calculation holding at slightly negative. This will help keep calcium deposits and probably help a lot on your salt cell contamination. I had mine for over 2 years before we sold the house and we ran/used the pool year round a LOT. Never had to clean the cell once and it was still running at the original setting of 40% when we moved out.

I hope this is helpful.

Chris
 
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setsailsoon said:
Bill,

Looking back at your logs looks like you may be running TA too high. As Marty recommended quit adding baking soda and let TA drift down to 60 or even below. I ran about 50 ppm with no problem and it stabilized the pH. We never let the pH get over 8.0. I kept it around 7.7 and tried to avoid higher than 7.9. Eventually I went to borates and that helped tremendously. I think it also just took way more time for my pool to cure than most. After several years I was down to adding acid about once per month with borates. When you get the pH back in range of TFP recommendations you'll see your CSI calculation holding at slightly negative. This will help keep calcium deposits and probably help a lot on your salt cell contamination. I had mine for over 2 years before we sold the house and we ran/used the pool year round a LOT. Never had to clean the cell once and it was still running at the original setting of 40% when we moved out.

I hope this is helpful.

Chris
Click to expand...
Chris,
I thought lower TA would cause the pH to move more...in other words, higher TA would stabilize my pH. Sounds like this may not be true. Since my pool is only a year old, should I hold off on trying borates? I'd rather not add borates and make things more complicated for me unless its necessary.

Thanks
 
wjmano said:
Chris,
I thought lower TA would cause the pH to move more...in other words, higher TA would stabilize my pH. Sounds like this may not be true. Since my pool is only a year old, should I hold off on trying borates? I'd rather not add borates and make things more complicated for me unless its necessary.

Thanks
Click to expand...
Wj,

Good thinking to delay borate addition. I would only do this if you can't control it first with adjustments to lower TA. I strongly recommend you take the time to watch the pH TA that Marty provided. I can tell you I ran 50 and had huge improvement. I don't know if borates were really required long term or if it just took way longer than normal for my pool to cure. In our new pool I'll try to get by with low TA for a while. I have nothing against borates other than I don't want to add chemicals that aren't needed. There are a lot of people that say borates do many different things to water color/clarity and a few other things. I never saw any of this. But pH stabilization was definitely dramatically improved.

Chris
 
setsailsoon said:
Wj,

Good thinking to delay borate addition. I would only do this if you can't control it first with adjustments to lower TA. I strongly recommend you take the time to watch the pH TA that Marty provided. I can tell you I ran 50 and had huge improvement. I don't know if borates were really required long term or if it just took way longer than normal for my pool to cure. In our new pool I'll try to get by with low TA for a while. I have nothing against borates other than I don't want to add chemicals that aren't needed. There are a lot of people that say borates do many different things to water color/clarity and a few other things. I never saw any of this. But pH stabilization was definitely dramatically improved.

Chris
Click to expand...
Thanks for the help Chris. I'll hold off on the borates and try a lower TA level.
 

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I had high TA (100+) before and was using HEAPS of acid to try and keep a lid on pH. Finally, got TA levels down and acid usage dropped. But the pH would still try to drift above 8, which is the limit of my test kit, so I would have to add small amounts of acid quite often to keep it at 7.8 or below.

Since adding 30ppm borates my pH is either 7.4 or 7.6. I haven't added acid in.. bloody heck.. 5 months (had to scroll a long way in Poolmath to check). The addition of Borates seems to have shifted the natural balance point lower and now it just sits there happily. I haven't added bicarbonate in well over a year and in that time my TA seems to drift between 60 and 90 on its own. CSI is a touch low, so I might need to add some bicarbonate. It will be interesting to see how well borates and bicarbonate play together.
 
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wjmano said:
Thanks for the help Chris. I'll hold off on the borates and try a lower TA level.
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We recently got a solar cover and the reduced gas exchange (presumably) has basically stopped the upward pH drift that occurred prior to the cover. I've had to purchase some pH increase for the first time! The carbonate equilibria in pools for a given alkalinity is driven by the partial pressure of CO2 in the atmosphere...even at 50ppm TA the equilibrium pH is over 8
 
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