pH bouncing back after numerous tweeks!

nanobooboo

Bronze Supporter
Jul 20, 2019
19
Cottageville SC
Just emptied my 225 gallon hot tub yesterday, and cleaned it out with Ahhsome. Refilled it today but can't get the pH to level out. Started out, the TA was 160 and the pH was 8.7. Using pool math, and many adjustments using muriatic acid, the lowest reading I ever got was 7.6. Finally happy, I checked it half an hour later and found it was back up to 8.3 with the TA at 160. Tried once again to correct it - the last time the TA was 110 and the pH at 8.5. I thought maybe it was a glitch with the digital pH tester, so checked my tap water - I'm on a well - and it read 9. Then I rechecked the hot tub water with the Taylor kit and it was at the very high end. Lastly I used a test strip and got the same range. Any ideas??
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Using pool math, and many adjustments using muriatic acid, the lowest reading I ever got was 7.6. Finally happy, I checked it half an hour later and found it was back up to 8.3 with the TA at 160.
Just to confirm .... you're saying that the pH climbed from 7.6 to 8.3 in 30 minutes? Hummmm. :unsure: Sounds like a testing issue. We can't rely on the test strip we know that. The digital tester results might be good to know if the meter is calibrated correctly and still accurate. Which Taylor kit are you using to test the pH, and can you tell us how old the reagent is?
 

nanobooboo

Bronze Supporter
Jul 20, 2019
19
Cottageville SC
Absolutely! The reagents and the pH digital tester were all purchased in late July when I joined the forum, so they are all fresh. I'm using the TF100 test kit, which included the pH tester. I was very careful calibrating the tester. The test strips came with the hot tub and have an expiration of 09/2020. You confirm my thoughts exactly on whether my supplies or methodology were glitchy, hence double and triple checking my results. I even researched whether my muriatic acid could be expired and/or degraded, but that doesn't seem likely since it was tightly capped.

I just checked it this morning and the pH is 8.3...

I get pretty quick pH drops when I test a few minutes after adding the recommended amount. I have the jets going full blast the whole time per everything I've read. Here's my log:

Time>> pH TA
1423>> 9
1506 >> 8.6
1559 >> 8.7
1748>> 8.7>> 160
1807>> 8.3
1823>> 7.6 >>>>> 16 minutes! *****
1857 >> 8.5>> 110

Each one of these corresponded to the pool math suggested additions, using the 31.45 muriatic acid.

At this point, I'm out of ideas, but will take some water and have it tested at the pool story to confirm my readings. ANY suggestions??? Thank you for replying and sharing your expertise...I really need it! o_O
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
I wouldn't bother with the pool store testing. Save a trip. Between your R-0014 drops/viewer and the digital meter, you should be quite close with your pH results. Sometimes I use the digital with my viewing of drops just to make sure my eyes aren't playing tricks on me. :crazy: So if between the drops and meter you're seeing an elevated pH - it's elevated. Your TA is still a bit high, so between that and the jets on full (aeration) that's probably contributing to your quick pH rise.

I would do this: Let the water circulate but not on high if possible. Consider your pH 8.2 (even though it may be higher) and dose with enough muriatic acid to lower the pH to 7.2. Use the PoolMath tool or APP to help with the dosage. That should do two things - lower the pH and TA. With the tub running, I suspect pH will climb again, so when it gets high (8.2 or more), repeat the acid process. Over time the TA should fall down which should help. Try to get the TA to about 50 -60 and that should help considerably. Below are a couple great pages to help you as well. Let us know if this helps.


 

nanobooboo

Bronze Supporter
Jul 20, 2019
19
Cottageville SC
OK, had chores to do in town today, but will start on it again tomorrow morning. Without any additions, and just the regular circulation filtering, the pH was 8.6 again. (And thanks for sparing me the trip to the pool store). I had great success this summer using SLAM to clear an algae invasion. This hot tub has been a challenge, and I even have a couple posts trying to sort out the progression of the testing, etc. I'll get some rest and tackle it again -no fear! Thanks!