MA not bringing down TA

[cjshelley]

here's a link to my pool for review: PoolMath Logs

this is our first pool that came with the house we bought and is ~20 years old. It was poorly maintained and had excessive CYA and no indication it was properly balanced so we drained it and started fresh and converted to SWCG (pentair IC40).

I've been trying to dial in my baseline to maintain and finding that I just can't seem to lower TA beyond 100 as tested with the Taylor 2006C.

I am using 20baum 31.45% MA to drop pH to 7.2 and aerating with SWCG and spa jets to bring it back up to 7.6 but the TA remains to be wholly unaffected after 4 tries.

ONE time it tested at 80-90 24hrs after the MA addition but I consider I must have made some mistake with my test because the very next day it tested 110 as shown in every other test I've performed for TA.

I run the SWCG at 20% for 7 hrs or so and I can't figure out why I just can't move the needle on TA. Is there something about the SWCG that prevents it from lowering? I recently added borates to combat pH creep but the TA phenomenon has remained identical both before and after the addition of borates.

I've tried to search the forums and haven't found anything helpful unless I've missed something obvious... Can someone help me understand what's going on?

 

[mknauss]

Do not worry about the TA. When your pH gets to 7.8 or 8, lower it to 7.4 with acid. Do continue to test the TA as you need the value in Poolmath to determine your acid additions.

 

[Rancho Cost-a-Lotta]

I've tried to search the forums and haven't found anything helpful unless I've missed something obvious... Can someone help me understand what's going on?

Maybe high TA fill water? Have you tested it. If nothing else, it may explain why TA is pushing back against your efforts.

 

[cjshelley]

Do not worry about the TA. When your pH gets to 7.8 or 8, lower it to 7.4 with acid. Do continue to test the TA as you need the value in Poolmath to determine your acid additions.

Thanks for the quick input! I seem to keep seeing split opinions on whether TA is that important and I thought the supporters/experts generally say that it is.

Are you thinking that I don't need to worry because it's 1) close enough, 2) will eventually be 80ish with continued acid additions and testing, 3) it really doesn't matter that much after all, or 4) some combination of any/all?

I'm confused by how acid addition isn't affecting alkalinity, nonetheless. It just doesn't make sense but I'm sure there's a missing piece of the puzzle

One thing that frustrates me about the Taylor test is that you have to monitor when it changes to "red" but there are a few different hues of pink/purple across 3-4 drops before I consider it "red" so there seems to be a lot of room for interpretation there

 

[mknauss]

4) some combination of any/all?

As you add acid, it will come down. But your fill water has high TA, so you will see it stabilize at some point depending on how prudent you are in managing pH.

One thing that frustrates me about the Taylor test is that you have to monitor when it changes to "red" but there are a few different hues of pink/purple across 3-4 drops before I consider it "red" so there seems to be a lot of room for interpretation there

For the TA test, you go until the last drop does not change the color. Then subtract that drop.

I'm confused by how acid addition isn't affecting alkalinity, nonetheless.

It is. Just not enough to see in the TA test every time.

 

[cjshelley]

As you add acid, it will come down. But your fill water has high TA, so you will see it stabilize at some point depending on how prudent you are in managing pH.

For the TA test, you go until the last drop does not change the color. Then subtract that drop.

It is. Just not enough to see in the TA test every time.

Brilliant thank you!