TA stuck high...how long to wait before worrying?

[MattM]

<6 month old pool, started up with TA ~120, brought it down to 80..then added borates and finalized cya, TA rose to 140....have been dropping ph and using acid for last 2 months (gone through at least 5 gallons of acid in that period), tested yesterday and TA was 170. Note that our pool has SWG, autocover, and intellichem to put small doses of acid in every 30-60 min. Our CH levels have stayed relatively reasonable ~320. Wondering what the next step should be....keep pool uncovered and connect some kind of aerator to returns? or just wait several more months to get TA down?

 

[ROB N]

It would help to have a complete set of test results, so we could know what your PH is. But just keep lowering the ph to 7.2 and TA will come down over time. The SWG can cause the ph to rise so that will give you the opportunity to keep adding MA to keep lowering the PH. The high TA will cause your ph to drift.

 

[MattM]

intellichem ensures ph doesn't exceed 7.32, I've been dropping it to 7.1/7.2 every few days.
cya 30, temp 89, fc 5, cc 0, ch 320, borates 35. Water looks perfect.

 

[duraleigh]

TA is lowered by adding acid and aerating. It sounds like you are not aerating.

 

[MattM]

That's what I was wondering....how much effort needs to be put in aeration...and I'm assuming the borates are making it harder to reduce TA. We get decent wind in the afternoons here, so perhaps the answer is just to keep the pool uncovered during daytime for the next few weeks and see if that aerates the water sufficiently.

 

[Smykowski]

That's what I was wondering....how much effort needs to be put in aeration...and I'm assuming the borates are making it harder to reduce TA. We get decent wind in the afternoons here, so perhaps the answer is just to keep the pool uncovered during daytime for the next few weeks and see if that aerates the water sufficiently.

I think for true aeration, you need bubbles. Point the returns up so they break the surface.

 

[JasonLion]

A cover more or less completely stops CO2 outgassing, so the PH won't rise and you don't get an opportunity to add more acid.

 

[dschlic1]

Definitely need to find a way to aerate your pool. As for faster TA reduction, you should lower the pH to about 6.8. I found that keeping the pool at 6.8 until the TA is 10 to 20 ppm BELOW the desired TA works quite well. At first you will find the pH rise is quite rapid and will need a lot of MA. As TA lowers, things slow down. The last 20 ppm reduction seems to take forever!

 

[MattM]

As an update -- tested today and TA was 190. ouch. Note that I had put in additional cya over the weekend, I'm guessing it's possible that cya impacts TA? Otherwise, I'm not sure how TA could rise 20 pts over just a few days and roughly 50 pts over the last few months. If true, that would explain some things as I've had to add additional cya several times this season.

As far as pH goes, the pool normally rises about 0.01 pH every 1-2 hours while the SWG is enabled and managed by intellichem. So, there is a significant acid demand....but not necessarily associated with aeration. Given the high TA, I had to reduce the pool pH to 7.2 today to keep CSI slightly negative.

The pool has 3 returns that have minimal pointing capability...I can point them up somewhat, and have been doing so, but it is only visible as a modest ripple and forward motion on the surface near each. If we need something different, I'll have to build it on my own or buy it.