pH and TA

[JoeSmith]

I have a 20,000 gallon pool with a SWG.

I would like to lower my TA. It seems like that might help my salt cell longevity.

Anyway, the other day I added 1 quart of Muriatic Acid to the pool.

I started at:
7.9 pH
110 TA

This acid got me to:
7.5 pH
100 TA

But now, the pH is creeping back up again as it does with my SWG (as well as the TA)

I’m at:
7.6 PH
110 TA

There seems to be only so much room I have to go down with my pH every time I add acid. And it doesn’t seem to lower the TA enough.

I’d like to get my TA around 90 if I could, but then it seems like my pH would plummet.

Is there anyway to break out of this cycle so that I can manage my pH and it’s upward drift with my SWG, while getting my TA down to at least 90?

Thank you!

 

[mknauss]

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.

www.troublefreepool.com

 

[mknauss]

After you have reviewed the above, what is your CSI? That data is available by inputting your data into PoolMath

 

[JoeSmith]

That video was great! Thank you! I’ve read a lot on the internet, and that was by far the most helpful.

My CSI is: -0.12

Now I understand why my TA has been drifting up. My CYA levels were negligible, so a few weeks ago I added 4lbs. of CYA. This raised me up to about 25 CYA (although that is not measurable on my Taylor test kit, so I’m sort of guessing). From what I understand from your video, this raised my TA up by about 8 or so.

I added 1 quart of MA, which probably dropped my TA down by about 6 or so.

My CH was at 260, so I added 4 lbs. of Calcium, and now I am up to about 280.

As for my SWG, I clean it every 3 months, and if I see scale I remove it or use MA to give it a bath. There has never been a problem or too much scale buildup.

I’m considering recommended levels for my pool:

CH: 300
TA: 90+
CYA: 30-50

I would have to add more stabilizer and calcium - not too much - probably 5-10 lbs. at most for each.

And I would also lower the TA by adding a quart of MA a week. Maybe after a month or so of this I could get the TA under 100.

However, since my CSI is good, should I not be doing this? Do you think my plan is ok? I heard what Matt said at the end of the video - don’t make work for yourself by trying to get to certain values for each chemical…. but yet, the individual values seem out of range even though pool math says my CSI is good.

Thanks again! The video was great!!

 

[mknauss]

As you get rain overflow you need to watch your CH and keep it above 250-300 ppm. Do manage the CSI, and as you say, yours is fine now, so no need to make major changes. If pH rises too fast, then let the TA lower over time while managing the pH. And that might mean you need a bit more CH.

Great you enjoyed the video discussion. Lots more on TFP-TV

 

[JoeSmith]

Thank you!

Just to confirm…

When you say “let the TA lower over time”, do you mean only focus on managing high pH with MA, and let that in turn lower TA?

I would watch my CH and pH first and foremost - and not so much the TA? Is it ok to raise the CYA now?

Sorry if I’m not quite following you. It’s been a crash course in the last month. I really appreciate your help!

 

[JoeSmith]

And more CH would help stabilize my pH, as calcium functions as a pH stabilizer?

 

[JoeSmith]

Lower TA: less pH stability
Higher CH: more pH stability

This is what your getting at?

Thank you!

 

[mknauss]

CH has no effect on pH stability.
When you lower the pH, it consumes TA. Unless you add more alkalinity, the TA will not rise. Alkalinity comes from fill water or chemical additions (baking soda, soda ash). CYA adds a small amount of alkalinity.

do you mean only focus on managing high pH with MA, and let that in turn lower TA

Correct, as stated above.

I would watch my CH and pH first and foremost - and not so much the TA? Is it ok to raise the CYA now?

Correct. And yes, if you need to add some CYA to get to 40 ppm or so, go ahead.

And more CH would help stabilize my pH, as calcium functions as a pH stabilizer?

CH does NOT act as a pH stabilizer. It is simply there to protect the calcium in your plaster.

Lower TA: less pH stability
Higher CH: more pH stability

If your TA gets too low, then pH can become unstable.
Again, CH has no effect on pH stability.

 

[JoeSmith]

Got it, thank you!