pH drifts up at target TA

[hex52]

My pool is about a year old and had high TA a few months ago so I tried to bring it down, which I did successfully. At this point the only chemicals I've only used was trichlor, liquid chlorine, and muriatic acid.

Then my TA was dropping (60) below my target range (70-90) because I was adding MA to keep pH within range, so I began using baking soda to bring it to 80 TA.

But I noticed at 60 TA, pH was more stable and at 80 TA, pH drifted up.

Is low alkalinity bad?
Is it secondary to controlling pH?
Can I keep TA lower than the recommendation since 60 TA is stable for my pH?

Check out my PoolMath logs for additional information

 

[Texas Splash]

But I noticed at 60 TA, pH was more stable

I'm in the same situation. I find the pH stabilized around 7.6-7.8 longer which also helps to off-set the slightly lower TA. A TA of 60 should be fine. I can't see your logs, but I suspect your CH level is a bit elevated, so that helps as well. I wouldn't raise the TA unless it drops below 60. Then I would only add enough baking soda to get it back to the 60-70 range to help reduce the pH yo-yo game.

 

[hex52]

My CH is right on the upper end of the recommended range. I plan to wait until September to give some time for CYA to climb then do a partial drain to bring it and CH down.

I thought I read somewhere about new pools causing pH to climb. Perhaps this factor is causing mine to climb even with TA 80?

Log and summary below:
PoolMath Logs

==========================================
hex pool
------------------------------------------
Build Type: Plaster
Volume: 12500 gallons
------------------------------------------
Latest Test Result Summary:
FC: 4.5 (2 hours ago)
CC: 0.0 (2 hours ago)
pH: 8.2 (2 hours ago)
TA: 80 (2 hours ago)
CH: 350 (7 days ago)
CYA: 45 (7 days ago)
TEMPERATURE: 86° (2 hours ago)
CSI: 0.64 (2 hours ago)
==========================================

 

[tim5055]

CH 60 is fine. My pool stabilized with TA 50.

Below 40 you need to watch the TA like a hawk. Bel;ow 40 is a bad place to be as this is getting close to letting your pH crash....