Disappearing CYA

[RASelkirk]

Since switching over to salt, I've prolly thrown in $500 bucks worth of CYA and never seem to achieve 50 and hold it for more that a few days. I've become content to let stay at zero and just up my chlorinator setting...

Russ

 

[Newdude]

Hey Russ !!! We need more info here but something ain't right. How are you testing ?

CYA doesn't go anywhere and if you could find a way to wipe it out in a few days, you'd be buy-your-own-island rich. Ammonia will kill CYA but that also wipes out FC in a matter of minutes. Does the FC hold from the SWG ?

 

[PoolGate]

Yes quite odd following to see what happens.

 

[Mdragger88]

Aside from inaccurate test results,
There was some “less potent” cya floating around on Amazon that some users reported not giving the desired results.
What cya were you using & did you use the sock method to introduce it to the pool?

 

[mgtfp]

How about salt and CH, any anomalies there? Is there a chance you have a leak and the autofill keeps replacing the losses?

 

[Toxophilite]

There should be a difference between hard time achieving a level and not being able to hold level. If it's purely the latter, sounds more like you are losing water.

 

[HermanTX]

Following as well. as others have stated - CYA just doesn't disappear. 50% of the people on this forum would be clamoring on how it was done without draining the pool.
It may be helpful to post a full set of Test Data.
If you use Pool Math app to track test results - link the data to your profile.

 

[Methuselah]

This is the 2nd post on this sub-forum for disappearing CYA ... neither seem to acknowledge it actually happening. It's OK to speculate improper testing (or pool store involvement). That might be my first guess to actually

However, one item in an older forum many years ago run by Ben Powel (I think the CYA chart was his?), a trick of his, was in pools so large that it was expensive or impractical to dump water, his advice was to let it turn green. He said algae eats CYA.

Just a thought, but could be an algae bloom starting to show up?

 

[Donldson]

Algae does not eat CYA. There is a bacterial strain that can consume CYA and convert it to ammonia, but this bacteria has no chlorine tolerance and will only show up in a pool with zero FC. The ammonia left after this conversion also creates a massive chlorine demand and creates considerable CC's when treated, both of which stand out in test logs like a sore thumb.

This is something that happens in neglected or closed pools, not in a pool that is being actively cared for. The pools in question do not appear to be neglected nor are the signs of an ammonia conversion present in any data.

 

[Methuselah]

Algae does not eat CYA. There is a bacterial strain that can consume CYA and convert it to ammonia, but this bacteria has no chlorine tolerance and will only show up in a pool with zero FC. The ammonia left after this conversion also creates a massive chlorine demand and creates considerable CC's when treated, both of which stand out in test logs like a sore thumb.

This is something that happens in neglected or closed pools, not in a pool that is being actively cared for. The pools in question do not appear to be neglected nor are the signs of an ammonia conversion present in any data.

OK. So letting the pool turn green will do the trick, or are you saying it's a maybe? I've never needed to try this...

 

[Donldson]

OK. So letting the pool turn green will do the trick, or are you saying it's a maybe? I've never needed to try this...

Maybe about 1 in 20 chance it will leave you with no CYA and a pool filled with algae and ammonia that will take a truckload of chlorine to clear. 19 out of 20 times you will be left with a green pool and the same CYA level.