High pH

Tim van Doorn

New member
Feb 12, 2021
Brisbane Australia
Apologies in advance, but I am an oldy (70 years) and my knowledge of the etiquette for forums is very limited. I have a problem with my pool in that the pH keeps going high >8.0 despite adding numerous litres of acid. The acid brings it down to the acceptable range, but within a week or so, the pH is back up high (pool is not used much). Test strips indicate all other parameters are around normal except that the total hardness is high (>1000).

By way of background, my pool developed a crack in Jan 2020. I had the crack repaired and a new layer of plaster lining was put in to give a good cosmetic finish. At first I was able to keep all parameters in normal range, but the pH problem is slowly getting worse. A search of the net would indicate the hardness is the issue to be sorted. Some suggest draining half the pool and filling with fresh water - but it was only refilled last August, so I am reluctant to do this. Others have suggested adding Borax (17kg) to soften the water but I'm not sure this will help. Any comments would be greatly appreciated.




Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Your TA level is integral in knowing why your pH is rising. Also any aeration of the pool water.

Test strip is not reliable nor accurate. In Australia, Clear Choice Labs carries a proper test kit that is equivalent to a Taylor K2006 which has the tests you need to properly manage your pool water chemistry.


Bronze Supporter
Jan 13, 2020
Sydney Australia
Pool Size
Salt Water Generator
G'day Tim and welcome to the TFP forum,
As mknauss has pointed out having a decent test kit is very important for you to manage and take care of your pool. The pool shop testing is unreliable and inconsistent, just ask the thousand of members on here!
Once you have your test kit post your results here and ask away. The forum experts will help you with any pool issue you have. Also if you can update your signature in your profile, this will also help answering your questions. The signature is basically a list of what equipment and type of pool you have.
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