Why is TA goal different in pool math vs directions in TF testing kit?

[Rq120]

So talk to me about TA. In the Pool Math app, it sets my goal TA to 70-90. However, in the instructions for TF testing kit it says "Good TA readings will be around 100-120 for manually chlorinated pools"

Why doesn't Pool Math have a different goal for TA. Or at least a larger goal range to take manually chlorinated pools into consideration?

Also, am I correct in my understanding that a high TA will drive pH up? My pool seems to be very stable in the 7.5-7.8 range. However, I'm trying to learn because we are getting new plaster next month and I want to have a good understanding of chemistry so I can take care of my plaster correctly during the first 30 days and beyond.

My results from today just as an FYI.
FC 8.0
CC 0
PH 7.6
TA 120
CH 575
CYA 140
CSI 0.31

 

[Jimrahbe]

120,

TA is the last chemical that we try to adjust... As long at your pH is stable, just leave TA alone... Any TA above 50 is just fine, as long as your pH is happy.

I see your CYA is a "tad" high, but assume you will take care of that when you replaster..

Thanks,

Jim R.

 

[Rq120]

120,

TA is the last chemical that we try to adjust... As long at your pH is stable, just leave TA alone... Any TA above 50 is just fine, as long as your pH is happy.

I see your CYA is a "tad" high, but assume you will take care of that when you replaster..

Thanks,

Jim R.

Exactly on the CYA! City water is expensive so I'm limping my pool along until I drain for the remodel. I just recently found the TFP method so I quit pucks a few weeks ago.

I wasn't looking to adjust TA, just wondering why Pool Math doesn't have a larger range or isn't 100% consistent with the instructions in the testing kit. Someone could look at Pool Math and think they are out of range.

 

[mknauss]

The recommended ranges are built to maintain the pool water CSI in range, without having to teach everyone about CSI. There are discussions about how to best manage that going forward.

Do realize the ranges are that, ranges. And if your pool water likes to be out of range in one or more parameter, then using the CSI tool is applicable.