TA test confusion

[caspiansails]

Hi, I am new to the forum and we have had our AG 32' Doughboy for about a month now. I was using the test kit that the pool store gave us - Pentair 56 I think which has drop tests for chlorine, PH, TA and Acid Demand. I just purchased a Taylor TF-100 kit. The issue I have is that their is a very large difference in the TA results between the two tests. The Pentair 56 returns 170 and the Taylor 340. I did these both twice with the same results and had my wife also do the tests with the same results. Not sure which to believe.

Other numbers
FC 1
CC 0
TC 1
PH 7.8
TA 170 or 340 depends on which one to believe
CYA 35
Temp outside today about 105F

Thanks for any help or experience with these test kits. I did not do an acid demand test since the PH was not any higher.

Rob

 

[duraleigh]

The lowest number from the Pentair 56 is probably correct on the TA test.

When the R-0009 Reagent is fresh, (it's the one where you count the drops 'til the color changes)there is an issue with static electricity that frequwently causes it to "jump" off the dropper tip so you end up counting tiny drops instead of fully formed ones.

The workaround (it'll go away on it's own soon) is to wipe the dropper tip every two or three drops with a damp cloth. This dissipates the static and you get a more accurate test.

 

[caspiansails]

That makes sense to me re the testkits. Actually it is a pentair 98 not that it matters but I did post it incorrectly. I did notice the drops were very small on the R-0009 Reagent so that sounds very likely.

Is it worth adding muriatic acid at these levels? I did an acid demand test with the pentair and it only took one drop to bring the ph down to 7.6 and according to the chart that would mean adding a pint of muriatic acid.

 

[duraleigh]

We've always suggested 7.2-7.8 as normal, so your at the high end of normal. If your pool is happy there, I'd leave it. Do not let it get up and stay in the 8's.