CYA issue after SLAM

[Phack1]

Before starting SLAM I checked CYA and it read 70. Used Taylor reagent, exp date of 5/26. I thought that was strange, since I ran at 60 all year last year, drained half of pool water off for winter and pool refilled this year with rain and a couple thousand gallons from well. I retested with different water four times and got the same reading of 70 each time. So, ok, performed SLAM based on CYA of 70. Finished SLAM, meeting all criteria and just for chuckles, retested CYA when I went out to test other chemicals. CYA is now barely reading 30! It’s probably lower that that but my comparator doesn’t go any lower, I’m at the top, and to be honest, I can still see dot.

I read cold water can cause a false low, but my original four times readings were probably in colder water, as we’ve had some 80 degree days. I brought some water inside and am going to test again once it warms. But, if it was the cold water, wouldn’t my original number of 70 been low? One note, when I tested before SLAM it was a very sunny day. I put my back to the sun and read. Today, when I tested, it was cloudy with no sun.
So, now I’m very confused about where my FC should be. Would the CYA drop like that after SLAM? Hoping someone can clear up my confusion because now I’m ripping my hair out and frankly annoyed I spent over $100 on 32 bottles of chlorine for SLAM I might not have needed to.

 

[Bperry]

Before starting SLAM I checked CYA and it read 70. Used Taylor reagent, exp date of 5/26. I thought that was strange, since I ran at 60 all year last year, drained half of pool water off for winter and pool refilled this year with rain and a couple thousand gallons from well. I retested with different water four times and got the same reading of 70 each time. So, ok, performed SLAM based on CYA of 70. Finished SLAM, meeting all criteria and just for chuckles, retested CYA when I went out to test other chemicals. CYA is now barely reading 30! It’s probably lower that that but my comparator doesn’t go any lower, I’m at the top, and to be honest, I can still see dot.

I read cold water can cause a false low, but my original four times readings were probably in colder water, as we’ve had some 80 degree days. I brought some water inside and am going to test again once it warms. But, if it was the cold water, wouldn’t my original number of 70 been low? One note, when I tested before SLAM it was a very sunny day. I put my back to the sun and read. Today, when I tested, it was cloudy with no sun.
So, now I’m very confused about where my FC should be. Would the CYA drop like that after SLAM? Hoping someone can clear up my confusion because now I’m ripping my hair out and frankly annoyed I spent over $100 on 32 bottles of chlorine for SLAM I might not have needed to.

CYA does not drop unless you replace water, though it can degrade 5-10ppm each month. Which test kit are you using?

 

[Phack1]

CYA does not drop unless you replace water, though it can degrade 5-10ppm each month. Which test kit are you using?

That’s why I thought it should’ve been lower when I did test before I Slammed. About half was replaced so 30 should be my number based on last year’s number, correct? I have the Taylor k-1515 FAS-DPD kit I’m using right now, have the k-2006 on order, I’m using the comparator tube for CYA test from the HTH 6 way test kit I have from last year but using a bottle of Taylor reagent for testing CYA.

 

[Bperry]

That’s why I thought it should’ve been lower when I did test before I Slammed. About half was replaced so 30 should be my number based on last year’s number, correct? I have the Taylor k-1515 FAS-DPD kit I’m using right now, have the k-2006 on order, I’m using the comparator tube for CYA test from the HTH 6 way test kit I have from last year but using a bottle of Taylor reagent for testing CYA.

Is the HTH comparator tube designed to use the crushed up tablets for CYA or the normal Taylor reagents? How old are the reagents?

You use whatever the latest test results are. Earlier test could have been error especially if the sample wasn’t 70F. Don’t sweat it, just go forward. I’d probably advise not mixing matching test components as well.

 

[Phack1]

Is the HTH comparator tube designed to use the crushed up tablets for CYA or the normal Taylor reagents? How old are the reagents?

You use whatever the latest test results are. Earlier test could have been error especially if the sample wasn’t 70F. Don’t sweat it, just go forward. I’d probably advise not mixing matching test components as well.

The HTH uses the liquid. I’m using a bottle I bought end of last year but exp date is 5/26 so I figured still good. Kept inside at all times except when testing. I wanted the CYA lower anyway, just annoyed I probably over bought chlorine for the SLAM. I’ll use 30 as my level and go from here. Thanks.

 

[HermanTX]

The HTH uses the liquid. I’m using a bottle I bought end of last year but exp date is 5/26 so I figured still good. Kept inside at all times except when testing. I wanted the CYA lower anyway, just annoyed I probably over bought chlorine for the SLAM. I’ll use 30 as my level and go from here. Thanks.

When you receive the K2006 test kit - post another set of full test results. That has a better comparator for CYA.