Question regarding testing TA with TF100 kit

Lykly

Gold Supporter
Nov 6, 2015
912
Ok ok
Testing for TA with the TF100 kit, when adding the reagent waiting for the water to turn from green to red, how far do you go? The water obviously turns red but continues to get even more red after a few more drops. Here is a real example I have currently. At 14 drops, the water turns red, but with drop 15, 16 and 17 it still changes color to a deeper red with each added drop, and at drop 18 it remains the same as where 17 left it. The way I understand it, this means a TA of 170, correct? I am under the impression you keep adding until the water stops changing, and not count the drop where it stops.... in my case the 17th drop equaling 170. Can someone please clarify for me? I am using acid to bring my TA down, started at ~290ish, so it is coming my way. Thanks
 

jblizzle

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May 19, 2010
43,260
Tucson, AZ
Always add drops until the last drop causes no further color change and do not count the last drop.

Same goes for all of the tests.
 

OTPirate

Admin
In The Industry
Oct 2, 2013
1,474
Creedmoor, NC
Good job on lowering the alkalinity using acid! Your numbers are sounding good. Yes, you are correct, when there is no more color change and you add that last drop, and then subtract that drop (number 18 for you)...that is your number. Good job!
 

Lykly

Gold Supporter
Nov 6, 2015
912
Ok ok
Thx all, I thought that's how it works but I wanted to confirm. Actually today was the first day I got in my pool and swam, it was awesome. My first-ever pool, and all the work I've done and the weather finally cooperated, I was finally able to get in and swim. 80 degrees outside and 70 degree surface water temps! [emoji15]


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Lykly

Gold Supporter
Nov 6, 2015
912
Ok ok
I have a question concerning my total alkalinity. I started out nearly at 300 when I filled my pool, and I have been adding acid, and it has came down slowly but steady to about 160 - 170 area. It has been stuck there for the last week or better. My pH slowly rises to 7.5 and I am adding acid to get it to 7.2, pretty much daily, just like I have always done since my fill, but my TA seems to be locked where it is. PH continues to adjust accordingly, but my TA is staying right where it's at. Prior it came down a little bit, pretty steady, but not anymore. Any ideas or advice? Or just keep doing what I'm doing?


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Lykly

Gold Supporter
Nov 6, 2015
912
Ok ok
That's the plan, to keep doing what I'm doing. I was just curious if this is normal? Is it not unusual for it to be dropping and then just get stuck? Overall everything's been going great, I have crystal-clear water and been enjoying the pool. I would like to get the TA down to where I don't have to adjust pH daily. I just did not know if I should let the pH rise higher and then adjust it, would that make a difference? Currently I've been lowering at 7.5, maybe I should let it rise a bit higher before adjusting?


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pooldv

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Aug 10, 2012
25,408
FL panhandle
What is the TA of your fill water? Has there been a little more evaporation recently? Yes, you will get more TA reduction if you let PH climb to 7.8 and then lower to 7.2.
 

Lykly

Gold Supporter
Nov 6, 2015
912
Ok ok
The TA of my fill water was right around 300. It came down slowly but surely until it got to this point and then pretty much stopped. Temperatures have risen somewhat, but not enough to cause any significant evaporation, and we have gotten some rain which I'm sure helps lower it. So far I have not had to add any water since the rain has pretty much maintained it. I will let it rise to 7.8 before I lower to see if that helps. I'm sure everything is fine, I was just curious why it stopped dropping at the rate it was. It appears that when you have a lower TA, the lowering process slows down. Thx


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Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
22,069
San Dimas, CA (LA County)
The TA of my fill water was right around 300. It came down slowly but surely until it got to this point and then pretty much stopped. Temperatures have risen somewhat, but not enough to cause any significant evaporation, and we have gotten some rain which I'm sure helps lower it. So far I have not had to add any water since the rain has pretty much maintained it. I will let it rise to 7.8 before I lower to see if that helps. I'm sure everything is fine, I was just curious why it stopped dropping at the rate it was. It appears that when you have a lower TA, the lowering process slows down. Thx


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Yes, as TA gets lower it takes longer and longer for the pH to rise and less and less acid to get the same pH drop. A lot of things are like that - huge changes initially and then they get slower and slower. Let the air out of a beach ball. It comes rushing out at first and then gets slower and slower and five minutes later the thing still has air in it and you can barely see it shrinking. A red-hot chunk of metal plunged into a tub of water. In two seconds it goes from red hot to cool enough to touch. Five minutes later it's still warmer than the water in the tub. In Calculus, it's known as related rates. But enough trivia...

You might just check for static electricity buildup on the bottle of R-009. If it builds, the drops stick and are smaller than normal, so you use more, which gives a falsely high reading. The cure is to wipe the tip of the bottle with a damp paper towel before testing. See if that improves your TA reading.
 

Lykly

Gold Supporter
Nov 6, 2015
912
Ok ok
Thanks Richard, I appreciate the explanation and insight. I will wipe my bottle down with a damp cloth prior to the next test to see if that helps, but after you confirming that this is not out of the norm, I feel better about it. I will report back after I do my next test to see if it made a difference.


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Lykly

Gold Supporter
Nov 6, 2015
912
Ok ok
Checked it using a damp cloth, got 150. It's a bit lower, but also could be from the latest addition of acid. In any case, it continues to slowly drop everything seems good. Thanks for confirming


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grottoguy

LifeTime Supporter
Aug 24, 2014
452
NJ
Can the experts read the first post in this thread. From
Prior threads I understood that the TA in the example from the first post would be 140 because once it turns red you were not concerned with the degree of the redness. However, in the above posts you seem to be saying that you agree the TA is 170. I think that contradicts advice from prior threads.

Please clarify.
 

grottoguy

LifeTime Supporter
Aug 24, 2014
452
NJ
This is one of the threads where I thought it was said once you get blue you stop and ignore that future drops give you a darker blue. In case this paste doesn't work the thread was entitled "CH test weirdness"
CH test weirdness


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wpturner05

LifeTime Supporter
Mar 30, 2015
87
Reading PA
Always add drops until the last drop causes no further color change and do not count the last drop.

Same goes for all of the tests.
Whelp …. I learn something everyday!! I have not been doing the testing completely correct!! Thanks for the help all!!

- - - Updated - - -

Can the experts read the first post in this thread. From
Prior threads I understood that the TA in the example from the first post would be 140 because once it turns red you were not concerned with the degree of the redness. However, in the above posts you seem to be saying that you agree the TA is 170. I think that contradicts advice from prior threads.

Please clarify.
This is what I have always thought to be true as well …. looking forward to further insight ….
 

duraleigh

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In The Industry
Apr 1, 2007
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Sebring, Florida
As jblizzle points out, you are looking for a color SHIFT, not a change in intensity.

On ALL of these tests, the endpoint is when there is no further color SHIFT.

Be careful not to overthink these tests. When I test, I personally don't see much change in intensity but I do see the shift and it's pretty easy to see when it stops.
 

grottoguy

LifeTime Supporter
Aug 24, 2014
452
NJ
So correct me if I'm wrong but based on what you are saying Dave I think the TA in the first post of this thread would be 140. OT Pirate indicated it would be 170 and no one corrected that statement and I think that is what caused the confusion.
 

grottoguy

LifeTime Supporter
Aug 24, 2014
452
NJ
Ok, so if the answer is 170, then the advice from TFT Expert 257WbyMag (see link to thread CH WEIRDNESS in post number 15 above) is wrong. He said that "Your endpoint is just blue. Once you get to blue (not bluish purple), that's when you stop. There is no need to attempt to achieve a darker blue and it need not be a vivid or striking shade." I thought Chem Geek was confirming that position in the same thread when he subsequently said "It's mainly a change in hue and when that doesn't change then that's the end. It can be a little subtle to distinguish between a change in hue vs. saturation..."

When I test,the change in deepneess of color is usually just one drop, so it is not a major issue, but Lykly had a three point differential,and that is why I am laboring on the issue.