Hello and Question About TA Specification

Hap

New member
Oct 15, 2014
3
0
Fort Worth TX
#1
Hello everybody. Been lurking here for a couple of months. Implemented TFPC in October and the pool has never looked this good. Came across this site while searching for answers to what turned out to be a metal staining problem. Successfully resolved that with an ascorbic acid treatment. I coordinated that effort with some pool work that required draining, so the day after the stain cleared up, I was able to drain the water. When I refilled, I took off the SWG (as it had failed and needed replacement) and returned the pool to its original fresh water configuration, (I had already started using bleach when the SWG failed about a month earlier), and fully implemented the TFPC system. Up to now I've been able to find an answer to every single question that has come up by searching the site and forums, and there have been a lot, and I'm amazed at the wealth of information here, and very grateful... and feel validated in my general impressions of pool stores. My question about the TA spec is about the notation "TA 70-90+". What exactly does that plus sign mean? Thus far, I've been maintaining in the 70 to 90 range, but every time I look at that spec I wonder about it. Cheers!
 

Richard320

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TFP Expert
Jan 6, 2010
20,322
1
San Dimas, CA (LA County)
#2
Welcome! :wave:

If you're adding TA, you set the target to 70 to 90. It's not critical; If 3.5 lbs puts you at 70 and it comes in a four pound bag, dump the whole thing in and don't worry. If you have high TA fill water, you don't need to obsess over it unless you're at risk of scaling. That's what the + is for. If the pool is stable at 110 TA, leave it alone! Just plug 110 into poolmath as your target and carry on. Otherwise, you'll be tweaking the TA and messing up the pH and get caught in an endless cycle no better than letting the pool store salesmen prescribe for you.
 

Hap

New member
Oct 15, 2014
3
0
Fort Worth TX
#3
Interesting, and thanks. That is not an answer I expected, so now I'm wondering further. Are you saying that the plus sign means that there is no recommended or practical maximum? Or, is there some dependency? I've been buying baking soda in 13.5 pound bags. If PoolMath says I need 9 ounces, it seems like dumping in an extra 13 pounds might not be the right thing to do... or is it? Not trying to be obsessive, although my pool-owning neighbors think testing FC and pH every day is a little nuts, compared to what they (and I used to) do. Ha ha.
 

duraleigh

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Apr 1, 2007
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#4
Have you read Pool School? You will find pool school suggests a range of 60 - 120 in the article ABC's of pool water chemistry.

You can see there is a broad range telling you that it the most forgiving parameter that we test.

Unless you are having a specific difficulty, (like pH that is hard to control) leave your TA alone assuming it's within that range

What was the answer you expected? If 70-90 has been working for you, I see no reason to change it or worry about it.
 

Richard320

LifeTime Supporter
TFP Expert
Jan 6, 2010
20,322
1
San Dimas, CA (LA County)
#5
Interesting, and thanks. That is not an answer I expected, so now I'm wondering further. Are you saying that the plus sign means that there is no recommended or practical maximum? Or, is there some dependency? I've been buying baking soda in 13.5 pound bags. If PoolMath says I need 9 ounces, it seems like dumping in an extra 13 pounds might not be the right thing to do... or is it? Not trying to be obsessive, although my pool-owning neighbors think testing FC and pH every day is a little nuts, compared to what they (and I used to) do. Ha ha.
Overdosing TA will just cause your pH to rise extremely fast. It might also lead to Calcium scaling, if CH is high. And it wastes baking soda.

The prevailing rule here is to only add what the pool needs.

You're just overthinking things. Many people mechanically plug in recommended values to poolmath and then start dumping chemicals to achieve "perfection." If TA is high, you don't necessarily need to adjust it to 70-90. You can target the same value you currently have, even if it is over 90. That's what the plus is about. Then you won't need to add anything to fine-tune TA. It just takes practice to get the cause-effect thing and learn your pool's personality and appetite. It will become second nature after a few weeks. You'll actually be able to predict the test results with amazing accuracy before you've added the first drop of reagent.
 

Hap

New member
Oct 15, 2014
3
0
Fort Worth TX
#6
duraleigh,
Yes, I read Pool School, and I keep reading it, especially the sections on pool chemistry! Most enlightening. In the Recommended Levels article is the "TA 70-90+" spec I was asking about. In the article you mention, "(60 to 120, sometimes higher)" is what is stated. My interpretation was that for my pool (plaster with bleach) the correct spec was the "70-90+" subset of the larger "60 to 120" spec. 70-90+ is also what PoolMath uses. I'm just trying to find out what the plus sign means.
Right now, I'm getting the impression that the 70-90+ means to keep it above 70, and the target max is a "fuzzy" 90, (aka 90ish), and, as you noted, the ABC article sets a fuzzy (sometimes higher) 120 as a recommended absolute maximum level. Does that sound like a correct understanding?
To answer your other question, the answer I expected was an explanation of the plus sign. I just want to make sure I'm understanding the nomenclature in use here. Did not expect an answer saying I should dump in more baking soda than PoolMath recommended, simply because the size of the bag exceeded the PoolMath solution, especially since I've got a 13.5 lb bag!

Richard320,
Thanks for that clarification. I am starting to develop a feel for this, but you're right, I'm probably over thinking it. I've been adding 8-10 ounces of 31.45% Muriatic per day the last couple of weeks to keep pH within range, (which is down from what I was doing when it was hot here and using more Chlorine) and having read here how TA buffers pH, I've been staring at that TA spec, and got to thinking I might not be understanding what it meant. That plus sign is not in any other spec that I've seen and, well, I just thought I'd ask to make sure I wasn't missing something important. Appreciate your responses.
 

JasonLion

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May 7, 2007
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Silver Spring, MD
#7
You have the right idea, but the upper limit is fuzzier than that. There is no point in raising TA above 90, but if you discover yourself with a higher TA it may well not be a problem. The practical upper limit varies from pool to pool. If your PH is going up all the time, your TA is too high. In some pools TA at 150 will be fine, in others anything over 70 can be a problem. This really only comes up for people with high TA fill water, who can't avoid having high TA.