pH won't come down and test kit won't give accurate readings

[Turtles in AZ]

FC - 1ppm
CC - 1ppm
pH - 8 plus
TA - ?????(using taylor kit and reading is turning yellow, instead of pink, after about 15 drops
CH - 100ppm

This is a commercial pool used for swim lessons and it is tested several times a day when we are open, but we are closed for 2.5 days a week and when I returned after the weekend the pH was starting to test high, and a day later it was off the charts.
The readings have been like this for 4 days. I have brand new reagents and I know they are working absolutely fine because I have another pool in the same building that I'm receiving stellar readings on.
The water has been crystal clear the entire time.
HELP!

 

[Richard320]

Re: pH won't come down and test kit won't give accurate read

Several things are going on here:
1) CC is too high, FC too low. I suspect a testing error because..
2) TA test goes blue to yellow instead of green to pink when FC is high
3) If pH is above the upper limit of the test, it may very well be 9 (or better), in which case the pool calculator is not going to give you the proper dose of acid.

Solution: keep adding acid until pH comes down. With high TA and a SWG, pH will climb, and climb fast.

Also recheck that FC and raise it to eliminate the CC.

 

[PJ]

Re: pH won't come down and test kit won't give accurate read

Are you sure the chlorine reading is right? I've encountered pools where the chlorine is so high it bleaches the endpoint colors in a test. This would result in a "low" chlorine reading, a very purple ph reading, and a yellow reading for TA. Add an extra drop of thiosulphate to your TA test (at the appropriate time) to counteract the chlorine. Also you might not want anyone in the pool if this is the case.

 

[PJ]

Re: pH won't come down and test kit won't give accurate read

Also I would lower the chlorine before adjusting the ph....just in case....

 

[Turtles in AZ]

Re: pH won't come down and test kit won't give accurate read

I retested my CC and diluted it getting a reading of around 11 or 12. Then have slowly added acid and the pH has dropped, also shut off my auto-feed for my Chl for a bit so as to not over feed. Thanks a lot, I had been adding acid but I suppose it wasn't constant enough. Thanks for the help

 

[Turtles in AZ]

Re: pH won't come down and test kit won't give accurate read

PJ - I've had the pool closed, that's the nice thing about having two.

 

[y_not]

Re: pH won't come down and test kit won't give accurate read

I retested my CC and diluted it getting a reading of around 11 or 12.

Combined Chloramines that high? WOW!!!
That would mean this is an indoor pool, right?
What did you end up with for FC on this last re-test?

 

[Turtles in AZ]

Re: pH won't come down and test kit won't give accurate read

Whoops! That CC was supposed to be FC at 11 or 12. My CC is usually 0 or 0.1

 

[UnderWaterVanya]

Re: pH won't come down and test kit won't give accurate read

Whoops! That CC was supposed to be FC at 11 or 12. My CC is usually 0 or 0.1

So what are the right numbers? Also what specific test did you use to measure FC/CC?

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