How soon after adding CYA to pool can you recheck level?

Apr 6, 2016
329
Louisiana
Should I wait a day, a few days, a week? I was at 35 and want to bring it up to 70. It called for 70 oz of CYA, I only put 40 oz and it's been a few days. Was waiting to retest it and then add more from there if need be.
 
There's actually been a lot of discussion and some testing done by moderators, experts and guides on this issue. The legacy guideline on this has been wait up to a week after it has dissolved to retest CYA. Some have been able to measure CYA almost immediately after it has all dissolved. Others have issues measuring for several days or longer after it has dissolved. The variables are water temperature, how the CYA is added (sock near return, sock in skimmer, dump in skimmer) and perhaps others that aren't easily seen.

How did you add yours? It certainly doesn't hurt to retest after a few days but there is currently no change to the guideline to wait about a week before retesting, afaik.
 
There's actually been a lot of discussion and some testing done by moderators, experts and guides on this issue. The legacy guideline on this has been wait up to a week after it has dissolved to retest CYA. Some have been able to measure CYA almost immediately after it has all dissolved. Others have issues measuring for several days or longer after it has dissolved. The variables are water temperature, how the CYA is added (sock near return, sock in skimmer, dump in skimmer) and perhaps others that aren't easily seen.

How did you add yours? It certainly doesn't hurt to retest after a few days but there is currently no change to the guideline to wait about a week before retesting, afaik.

I added mine in a pair of very thin socks hanging in one of my waterfalls. I put it hanging in the morning when I left for work and it was pretty much fully dissolved when I got back (just had to squeeze it a few times). My initial thinking was to wait a week.
 
There is no harm in waiting a week, but the concern is that if you re-test before it is *fully* apparent in the tests and you feel you need more you might end up over-dosing it.

And we all know *that* would be a PITA!
 
It seems from the testing that the majority of the CYA shows up on the test within a day after it dissolves, however from my personal testing experience while running low 20-30 ppm CYA levels I can still detect a slight change 5-7 days after dissolving, This change may be so small it is not detectable at the more common 40-70 ppm CYA range however. There is also the issue that some brands of CYA seem to dissolve much easier than others, even though all range from slow to very slow to dissolve.
 
Keeping it in a "sock" could make it take longer to dissolve ? It seems pretty obvious to me that if you have an undissolved "lump" hanging around, it's not going to register fully no matter how long you have waited.

I followed the instructions on the (Clorox) container, and it registered as expected right away (the next day).
 
Keeping it in a "sock" could make it take longer to dissolve ? It seems pretty obvious to me that if you have an undissolved "lump" hanging around, it's not going to register fully no matter how long you have waited.

I followed the instructions on the (Clorox) container, and it registered as expected right away (the next day).
That's great that it worked for you, but what we post gets read by lots of people, not just the original poster. Our answers should apply as much as possible to all people. There are reasons we suggest what we suggest.
1) The granules do take a while to dissolve. If someone has added CYA directly to the skimmer to raise CYA while doing a SLAM, the granules are in the filter. If the filter loads up with algae and needs backwashing before it's all dissolved, then what? Nineteen out of twenty dollars' worth of CYA is gone. If the only CYA in the filter is what's already dissolved and the undissolved stuff is still safely in the skimmer basket or dangling in front of a return, what's lost? Not enough to even affect the test.
2) pouring too fast can clog the lines. This thread: Skimmer clogged from stabilizer is not the first time this has come up. A couple years ago someone had a chunk get caught in the impeller housing and it made a scary racket until it finally disintegrated.
3) You never know when it's all dissolved if it's inside the filter. You'll know when a sock is empty. There's some experimenting going on behind the scenes regarding how soon CYA will register. It has varied a bit, depending on brand and water temperature.
 

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