Does CYA disappear?

milesvdustin

Well-known member
Jun 7, 2015
169
Marion, IL
Pool Size
21500
Surface
Vinyl
Chlorine
Liquid Chlorine
Opening above ground pool. When i closed it last year and drained below the skimmer, it was at 50 for the cya level. I just checked it after filling at i have absolutely nothing. Does the r0013 reagent go bad? Or did i lose all my cya?
 
The chances are almost 100% you lost your CYA. We have learned it does disappear over a winter and will need replacing. No one is really sure what triggers it but it happens.

On the other hand, the CYA reagent is one of the most stable of the reagents we use so it is very unlikely it is the culprit
 
Yeah, I ended last year with CYA at 70 when the water went below 60. After that I only check FC and Ph for the rest of winter. So when the water stayed above 60 for a week or so I checked everything and the CYA was around 35 to 30. We had lots of rain this winter and it kept getting cold later this year than most years. I'm going to raise the CYA slowly with some left over tri-clor tabs and give the SWCG a few weeks rest. Or you can just buy some of that stabilizer from Wally World or where ever you get your pool stuff from. Just wait a week for the stabilizer to show up in you test if that is the way you chose to go. Good luck!
 
I threw a few trichlor tablets in a floater for now to add stabilizer until i can really get a good clean started this weekend.

- - - Updated - - -

I have about 7 of these 4 inch trichlor tablets. Pool volume is 13,500 gallons. Will each tab raise cya by 1 if im using pool math correctly?
 
I found this tid bit online...If this is true, then maybe we should be slamming and circulating our water first before checking CYA.

Pool / chlorine conditioner should only be added after properly testing its level. As I noted in the previous post, you should have your pool water tested about 3 to 5 days AFTER the pool has been open and operating to thoroughly "mix" and distribute everything that is in the pool's water - even last year's CYA; it didn't go anywhere over the winter. In truth, the water that contains the CYA is more dense than the rest of the water and therefore sinks to the bottom of the pool. That's why it's so necessary to circulate and filter the pool water for several days before having it professionally tested (most home test kits or strips don't test for CYA).
 

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