Opening in Chicago, PH & TA Relationship

[gingrbredman]

So my neighbor opens his pool recently, the PB throws in some kind of chemicals, they test with strips, and the one nice day, jumped in. Everyone felt all itchy and irritated (FG SWP), so something was wrong with the chemistry. He is not a TFP guy, but knows I am so reached out. I brought out my kit, full blown TF Test kit, Taylor salt kit, speed stir, all kinds of extra beakers and magnets and get to work.

The easy parts were low chlorine and no CYA. Easy enough to add stabilizer and crank up the SWCG cell. But what still stumps me is the relationship of PH and TA and the Poll Math app. Since this is not my pool, mine is not open yet, this will give me a lot of practice before mine is open in a few weeks. Pool is similar to mine, just a little bigger.

FC 2.5
CYA 70
PH 7.2
TA 220
CH 220
Salt 3400
CSI 0

Of course the PH and TA are out of range, but I think I am reading conflicting info of what to do in the Pool Math App

If I look at the PH, it tells me I need to raise my PH with Borax (or Washing Soda)



If I look at TA, it tells me to lower my PH with acid, but no recommended amounts, but my PH is already in the range it needs to be, according to the notes about how to handle TA.



Am I seeing that correctly? In the same test logs, I need to raise my PH with Borax, then lower my PH with acid and aeration.

While this may not be my FG pool, I do want to understand this conflicting information in case I come across it on my own in a few weeks. Similar pools, FG, SWCG, heaters, etc. Never had an issue with mine last year so really want to help a friend out, and understand what that means.

 

[mknauss]

Poolmath just uses the recommended levels and points to the mid point. You have to understand the relationship between the parameters. With a TA of 220, the pH will climb very quickly with any amount of aeration. Do be aware, if your kit is brand new, the TA reagent R0009 can have very small droplets the first few times it is used and thus imply a higher TA than expected.
"Sometimes a static electric charge can build up on the R-0009 dropper bottle tip, causing the drops to be smaller than usual and making the test read higher than actual. You can prevent this by wipping the tip of the dropper bottle with a damp cloth or tissue before you start and after each drop."

 

[gingrbredman]

Thanks for the quick reply MK! That reagent is not new, my own TA tests were always in line and never had to retest. I did also follow the instructions to the letter for the TA test, properly wiping the bottle. Should have mentioned I did the test three times, each time it was within one drop of each other.

You have to understand the relationship between the parameters

Yes! This is why I am posting this here, I just do not understand that relationship. On top of that, the app is telling me conflicting information based on the tests, and not understanding what they mean, is the reason I reaching out for help here.

 

[kellyfair]

Need to get that FC up some, it’s below minimum. Boost with LC, so SWG doesn’t have to work so hard.

 

[mknauss]

I just do not understand that relationship.

ABCs of Pool Water Chemistry

TA - Further Reading

www.troublefreepool.com

PH - Further Reading

www.troublefreepool.com

PH TA Relationship - Further Reading

www.troublefreepool.com

 

[ajw22]

Boost with LC, so SWG doesn’t have to work so hard.

SWG is built for hard work. No problem running a SWG for as long as needed to generate the chlorine. Use what you paid for.

 

[kellyfair]

Yes! This is why I am posting this here, I just do not understand that relationship. On top of that, the app is telling me conflicting information based on the tests, and not understanding what they mean, is the reason I reaching out for help here.

High TA will drive PH up. The way to lower TA is to lower PH.

So, if you aerate to get PH up, you can then lower with MA, and that will reduce TA. Then aerate again, to get PH up, and so on.

I don’t focus much on TA. If my PH is too low, I raise it, if too high, I lower it. TA falls in line.

SWG is built for hard work. No problem running a SWG for as long as needed to generate the chlorine. Use what you paid for.

I find it much easier to get FC where I want it, then use SWG to maintain it. That way I’m not spending a lot of time under minimum while SWG works.

If OP was at 3 or 4, and target was 5 or 6, then yep, the SWG will get him there with no algae concern.

 

[ajw22]

PH 7.2
TA 220

There is a missing piece to this story. Was acid recently added to the pool?

With a TA of 220 pH will not stay at 7.2 for more then a day.

pH and TA are about equilibrium. This charts illustrates the pH/TA relationship. The TA will move the pH toward a value of 1.

 

[ajw22]

I find it much easier to get FC where I want it, then use SWG to maintain it. That way I’m not spending a lot of time under minimum while SWG works.

My guess is @gingrbredman has no LC at his friends house and did the right thing in turning up the SWG. Use the tools you got.

 

[kellyfair]

My guess is @gingrbredman has no LC at his friends house and did the right thing in turning up the SWG. Use the tools you got.

I am not saying it was wrong to turn it up. I gave good advice that we typically give in this type of situation, but if he doesn’t have the ability to follow it, he doesn’t have to.

 

[gingrbredman]

This is why I come to this site every morning! Just a ton of great people here always willing to help out, and fast! I try to contribute where I can, but still new to this, and this one stumped me! Poor PB's understanding of water chemistry and unknown chemicals added before we even started (no response from the PB who opened) probably started this train off the tracks!

@mknauss , thanks for the links. I spend so much time reading the threads, and builds, and interacting with the people here, sometimes I forget there is that wealth of knowledge there at our fingertips. Sometimes finding people who have had these issues like mine are why I posted the question, and got a lot of great answers.

@kellyfair, thanks for the simple breakdown of the TA, PH relationship! Makes a ton more sense now that I read that, and have a clear understanding now of what to do next to get the TA and PH in line! Also, if this was summer, and had some LC on hand, and wanted to swim quicker, that suggestion would work. I know the FC is low, but since no one will be swimming quite yet, letting the SWCG drift the FC up will do the trick. Chicacgoland is still pretty cool, and maybe on the early side to open up anyway.

There is a missing piece to this story. Was acid recently added to the pool?

With a TA of 220 pH will not stay at 7.2 for more then a day.

pH and TA are about equilibrium. This charts illustrates the pH/TA relationship. The TA will move the pH toward a value of 1.

@ajw22 Thanks for that help as well! Yep, there is a missing piece, and really appreciate you noticing that. Really trying to help out a good neighbor who has had a lot of difficulty with his PB. When he came to open, he dumped some chemicals in the pool, unknown what they are, he wont respond, so guessing it had to be some kind of acid. That chart was also super helpful! I'm a TA PH expert now in a matter of minutes!

My guess is @gingrbredman has no LC at his friends house and did the right thing in turning up the SWG. Use the tools you got.

Correct, no LC on hand, really never had a need for it with the SWCG. Do not have any at my house either, same setup. As I said, with no swimmers in the next week, the tools to increase the FC is the SWCG. No need to "super chlorinate", just gonna let it drift up to the proper levels.

I find it much easier to get FC where I want it, then use SWG to maintain it. That way I’m not spending a lot of time under minimum while SWG works.

Good advice for sure. With full swimming season, this would get the FC to a level for everyone to get in. Just not in a rush to get the FC up, that was really one of the easiest parts of this puzzle.

Thanks again all for the quick help! Will have that PH and TA dialed in soon. The FC will drift up, and in a few weeks when it is nice enough to jump in, will have a TFP at my neighbors house, right in time for me to open up my pool and do the same

 

[kellyfair]

You bet, happy to help.