TF100 vs. Pool store results for TA - which is correct?

texasgirl2009

Gold Supporter
May 31, 2020
18
Dallas, TX
new to having a pool and trying to get this figured out.... Pool store has my TA at 70 (twice) and I have repeated the TF-100 testing 3x myself and is is much higher - 160-180. I think I'm doing it right, watched the video, etc (though I don't have a speed stir, I think I'm mixing it ok).
Is the TF-100 more accurate than my pool store testing?
 

Donldson

TFP Expert
LifeTime Supporter
Jun 12, 2009
4,569
NW Ohio
Pool stores often show Adjusted Alkalinity instead of Total Alkalinity. That is likely one reason.

If this kit is pretty new, are you wiping the tip of the R-0009 bottle between drops? If the bottle is extremely fresh then it can build up some static and cause the drops to jump off before they are fully sized. If you haven't tried that it might be worth trying to see if you get an especially lower result.

And an aside: please don't get your water tested at the pool store. They aren't reliable and can just have you second-guessing your own testing at a time where you're struggling to trust yourself. When I say that I trust someone on their first test with a TF-100 over a pool store, I really mean it. You might mess it up, but you have a vested interest in getting it right. Pool stores don't, accuracy doesn't affect their ultimate goals. Bottom line is we trust you. Try to trust yourself too. :thumleft:
 
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IceShadow

Gold Supporter
TFP Guide
Jun 8, 2019
2,177
Milwaukee, WI
The TA test is very accurate when done correctly. I’ve used it to verify my pool volume with baking soda addition.

Wipe the tip like Donaldson said above. Be sure you’re holding it vertically and allowing the drops to fall off the tip, only very gentle pressure. Try testing with these methods and let us know what you get. :)
 

tomliv

Member
Jun 7, 2020
6
MA
The first two times that I tested TA with the TF-100, I did not have the bottle vertically, and I did not wipe with a damp paper towel at the beginning and between drops. My readings were 150-160. I was using the smart stir (similar to the speed stir). The pool store test and test strips that I had were reading much lower (80-90).

I just tested TA for the third time using the smart stir ... holding the bottle vertically and wiping the tip at the beginning and between drops with a damp paper towel. The TA was clearly 80.
 

texasgirl2009

Gold Supporter
May 31, 2020
18
Dallas, TX
thank you !!!! I think I am lacking the confidence to believe my own readings :)
I rechecked now and even with making sure I am holding the bottle Vertically, wiping tip, etc. I am still getting:
TA -140
Cl - 0.5
pH - 7.8
CH - 175
CYA- 0
 

IceShadow

Gold Supporter
TFP Guide
Jun 8, 2019
2,177
Milwaukee, WI
Trust your results. TA doesn’t mean much anyhow - just need to know what it is to calculate CSI and to know how much acid to add. :)

More important to get CYA up to 30 and FC up based on that!