Unexpected CYA test result

Jump to latest Follow Reply
S

Sws

Silver Supporter
Jun 11, 2024
70
Long Island Ny
Pool Size
10000
Surface
Vinyl
Chlorine
Liquid Chlorine
Hi Everyone,

I just tested my water to see how well it held up over the winter. It visually looks absolutely perfect but this could be because its still early and cold. I plan on fully opening it May 1st.

Before the winter, I drained about 1/3 of the water to work on it and just filled it back to where it needs to be for the summer. I have NOT run the pump yet, so idk if this is simply a distribution issue.

Most numbers are where i expected them to be, but my CYA per the test increased, instead of decreased.

Numbers are:
Alkalinity 107
Calcium 118 (down from 184)
FC 6.5
CC .3
TC 6.8
Copper .37 (down from .5)
CYA 94 (up from 60)
PH 7.4

What is the consensus here? Run the pump and test again? Does CYA naturally rise when undisturbed for a period of time?

I appreciate the feedback.
 
Testing error likely. Pool water that is colder than 50 degrees will test wrong on CYA.

You want to have the pump running for 24 hours before you test. You also want warm the sample to room temperature for the CYA test.

Did you do the test outdoors in the sunlight?

Refresher... CYA - Cyanuric Acid Test
 
Last edited:
  • Like
Reactions: Newdude and Sws
PoolStored said:
Testing error likely. Pool water that is colder than 50 degrees will test wrong on CYA.

You want to have the pump running for 24 hours before you test. You also want warm the sample to room temperature for the CYA test.

Did you do the test outdoors in the sunlight?

Refresher... CYA - Cyanuric Acid Test
Click to expand...

Thank you. Its in the 40s and cloudy here right now and I did not let it warm up. Ill do it the right way tomorrow.
 
  • Wow
  • Like
Reactions: oledan and PoolStored
Newdude said:
I'm saying a digital tester was used for those results.

We have learned to stick with Taylor drop based tests. :)
Click to expand...

That doesnt mean that I didnt test it myself.

Has anyone compared numbers from a Taylor kit to this? If not, ill buy a Taylor kit tonight and post the comparison after running the pump.

sensafe.com

Pool eXact® EZ Photometer

Test your pool water with the Pool eXact EZ Photometer
sensafe.com sensafe.com
 
Sws said:
That doesnt mean that I didnt test it myself.
Click to expand...
Then I humbly apologize for implying otherwise. But 'who' used the digital tester is irrelevant. We don't give advice from them whether it's a handheld or a spin touch at the pool store. Sometimes they agree with Taylor, but we never know which time that is when it's presented.

Photometers are particularly bad at CYA.
 
  • Like
Reactions: oledan and PoolStored

Enjoying this content?

Support TFP with a donation.

Give Support
SWS,

So it appears to me that you are using test strips that are then read by a color comparator. Is that about right??

We call test strips "Guess Strips" as we don't have much faith in them.. :mrgreen:

I have a LaMotte Color Q, which I bought before I got on TFP..

Over time, I found that I could not get a very accurate or repeatable readings of TA, ALK, CYA.. It does a pretty good job on measuring FC and Ph... I guess my point is that digital testing does not necessarily mean accurate testing, it is just fast.

I had not seen that test kit before, thanks for the link.. :goodjob:

Thanks,

Jim R.
 
  • Like
Reactions: oledan
Jimrahbe said:
SWS,

So it appears to me that you are using test strips that are then read by a color comparator. Is that about right??

We call test strips "Guess Strips" as we don't have much faith in them.. :mrgreen:

I have a LaMotte Color Q, which I bought before I got on TFP..

Over time, I found that I could not get a very accurate or repeatable readings of TA, ALK, CYA.. It does a pretty good job on measuring FC and Ph... I guess my point is that digital testing does not necessarily mean accurate testing, it is just fast.

I had not seen that test kit before, thanks for the link.. :goodjob:

Thanks,

Jim R.
Click to expand...

I wouldn't call it a test strip. Its putting a reagent in the water and the photometer takes it from there.

I just bought a Taylor pro kit and some add ons from TFtestkits.net

Im curious how they compare.
 
Last edited:
Sws said:
That doesnt mean that I didnt test it myself.

Has anyone compared numbers from a Taylor kit to this? If not, ill buy a Taylor kit tonight and post the comparison after running the pump.

sensafe.com

Pool eXact® EZ Photometer

Test your pool water with the Pool eXact EZ Photometer
sensafe.com sensafe.com
Click to expand...
That tool is NSF/ANSI 50 L1 certified. But it doesn't mean much. Leslie's accublue is also certified and the Taylor reagents are way more accurate and the gold standard for testing.

Testing_Accuracy.jpeg

Testing_Accuracy.jpeg

 
  • Like
Reactions: Sws
Ill let everyone know exactly how each change compares. Ill do pump on for 24 hours tested cold, then ill warm the sample and test again. Ill do it with both the Sensafe and Taylor kit once it arrives. I wanted the Taylor kit anyway because the Sensafe Chlorine measurement tops out around 20 and I can't use it accurately during a slam.

I was expecting CYA numbers in the 40s, so I'm off by over 100%
 
Sws said:
I was expecting CYA numbers in the 40s, so I'm off by over 100%
Click to expand...
On top of you adding 1/3 fresh water, CYA also degrades a little each month. It's unnoticeable during the season in non desert climates, but it's really noticeable when we walk away from our pools for up to 8 months up here.

Between the natural decay and 1/3 fill water not mixed well, I would have guessed very little CYA or 0, and the tester is claiming 94.
 
  • Like
Reactions: Sws
Sws said:
I was expecting CYA numbers in the 40s, so I'm off by over 100%
Click to expand...
L1 certification is done in controlled environments with calibrated equipment and certified operators. LOL...
You and likely Leslie's are un/undertrained, likely not calibrated regularly an have varying environmental facts.
Why we trust Taylor reagents.
 
Last edited:
Sws,

When you initial use the Taylor kits you may be a little disappointed.. Only because it takes a couple of times running the tests to get used to it.. Like almost anything.. the first time is hard and then it become just routine..

Not sure which test kit you are getting, but make sure you get a speed-stir type of device.. It takes all the work out of the tests.. Of course that could be because I can't count drops, swirl the test tube and watch for a color change all at the same time... :mrgreen:

Thanks,

Jim R.
 
  • Like
Reactions: Newdude and PoolStored

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Top Bottom
Back
Jump to latest Follow Reply