Adjusted TA for CYA

Cmelser

Well-known member
Jan 18, 2020
141
Bradenton, Florida
Pool has been doing very well and testing is going well on my own. Today I had to run a sample to my Leslie’s store so I could get my CYA tested since I ran out of fluid and it’s been a while since I tested. They said my numbers were really good but said I needed to add 3lbs of Baking soda since my “adjusted TA” was 62, however my home test was 90-100. This appears to be new from them as I trust the guy who runs the store, he actually supports this site. He said that I need to always adjust because my CYA is running At 89. Pool seems perfectly fine to me. I know never trust a pool guy but he literally didn’t want to sell me anything and actually gave me R-13 fluid to fill my jug.
here are my numbers as I know you always want them.
FC-10
CC-0
PH-7.8
TA-100 maybe 90, might have miscounted but it’s been 100
CH-300
CYA-89 according to the store.
I had tons of problems last season with keeping my levels right so I want to be ahead of the curve. Any advice on the adjusted TA?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
36,041
Laughlin, NV
Pool Size
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Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Ignore it. Use your own test results. Any adjustments needed when it comes to calculating chemical additions is handled by Poolmath.
 

HermanTX

Gold Supporter
May 20, 2020
1,363
Katy TX
Pool Size
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Liquid Chlorine
There are 2 values for TA as you stated. For example a TA of 100 and a CYA of 90 creates an adjusted TA (called carbonate alkalinity) of 70. Basically the math is substract 1/3 of CYA value from the TA so 100-(90/3)= 100-30 = 70.
I read in another post that Pool Math makes the calculation in the program to provide the right data to calculate CSI.

In more technical terms from Taylor Technologies
Therefore, the total alkalinity titration measures both carbonate and cyanurate alkalinities. This affects water balance calculations because the alkalinity term in the Saturation Index equation is strictly carbonate alkalinity.
 

Cmelser

Well-known member
Jan 18, 2020
141
Bradenton, Florida
Ok, that makes sense, I do see that in the CSI part of pot math it does ask for CYA. According to my measurements I am in good shape there with my test results. So I will not adjust my TA to meet the Leslie results. The water feels slightly hard to me but according to everything it is correct so I will keep on rolling with it. Thanks for some explanation. Like I said only used them today for the CYA level and phosphates.
 

JamesW

TFP Expert
Mar 2, 2011
23,219
The adjusted alkalinity is the TA - (CYA x cf).

Cf is the correction factor, which is based on the pH.

pH........CF
7.0.......0.22
7.1.......0.24
7.2.......0.26
7.3.......0.28
7.4.......0.30
7.5.......0.32
7.6.......0.33
7.7.......0.34
7.8.......0.35
7.9.......0.36

For example, if the pH = 7.6, TA = 90 and CYA = 70, the adjusted alkalinity is 90 - (70 x 0.33) = 67.

There's no reason to target any specific TA or adjusted TA.

Overall, you want a TA that keeps the pH stable and the CSI in a good range.
 

EricJ320

Active member
Mar 27, 2020
30
Tennessee
Pool Size
23000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool Edge-40
The adjusted alkalinity is the TA - (CYA x cf).

Cf is the correction factor, which is based on the pH.

pH........CF
7.0.......0.22
7.1.......0.24
7.2.......0.26
7.3.......0.28
7.4.......0.30
7.5.......0.32
7.6.......0.33
7.7.......0.34
7.8.......0.35
7.9.......0.36

For example, if the pH = 7.6, TA = 90 and CYA = 70, the adjusted alkalinity is 90 - (70 x 0.33) = 67.

There's no reason to target any specific TA or adjusted TA.

Overall, you want a TA that keeps the pH stable and the CSI in a good range.
I actually came to the forums today to research this exact issue, so thank you for this information as I try to get my water balanced for the coming season. My only remaining question would be, when inputting my test results into Pool Math, does it make this correction factor to the TA when calculating both the recommended additions for adjusting TA and in the CSI calculation? Or do I need to essentially subtract 1/3 of my CYA value when logging TA value into the app?

I‘m grateful for this forum everyday, there so much information that helps a new pool owner like me that I can’t thank you guys enough for taking the time to share your wealth of knowledge. So thank you again!
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
23,655
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
I actually came to the forums today to research this exact issue, so thank you for this information as I try to get my water balanced for the coming season. My only remaining question would be, when inputting my test results into Pool Math, does it make this correction factor to the TA when calculating both the recommended additions for adjusting TA and in the CSI calculation? Or do I need to essentially subtract 1/3 of my CYA value when logging TA value into the app?

I‘m grateful for this forum everyday, there so much information that helps a new pool owner like me that I can’t thank you guys enough for taking the time to share your wealth of knowledge. So thank you again!
Pool Math makes all the corrections for you. Input the results directly from your Taylor tests. You don’t need to over think it. Pool Math keeps it simple for everyone.
 

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EricJ320

Active member
Mar 27, 2020
30
Tennessee
Pool Size
23000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool Edge-40
Pool Math makes all the corrections for you. Input the results directly from your Taylor tests. You don’t need to over think it. Pool Math keeps it simple for everyone.

Just put the raw numbers in Poolmath and it will do the work for you.

Thanks guys, that was the answer I assumed but wanted to make sure.