CYA zeroing out

[Southern Swimming]

Hi all,

Over the course of this swim season my team has had several issues maintaining CYA. First we had issues with Leslie’s granulated conditioner not raising CYA in some pools but working well in other pools. My employees would report inconsistent CYA readings that I chalked up to user error. I had all my guys switch to Leslie’s instant conditioner (pre-dissolved in water) and this seemed to remedy most of our issues until recently.

One of our clients pools turned green so I spent a couple weeks making visits myself to clean it up and testing FC, pH, and CYA almost every visit. Initially CYA was at 60ppm and pH at 7. I cleaned the pool up and handed the weekly visits back over to my employee and it immediately went green again. When I retested the conditioner it was at 0-10ppm CYA and 8+ pH.

To my knowledge, the only way CYA will decrease is by dilution with tap or rain water. We’ve been getting a lot of rain but for CYA to drop from 60ppm to almost 0 in the span of two weeks there must be something going on. The pool doesn’t have an automatic water leveler. My first assumption was that CYA being an acid could be neutralized by rising pH due to the back to back algae blooms. I’ve also read about high chlorine levels oxidizing CYA.

My questions are as followed:
1. Will algae blooms raise pH?
If so, will high pH neutralize cyanuric acid?

2. Could high chlorine levels from repeated shock treatments oxidize CYA?

3. What other chemical interactions can neutralize CYA?

All other info is helpful, thanks in advance!

 

[YippeeSkippy]

Good Evening, Southern Swimming....I've heard quite a few TFP users say their CYA has petered out unexpectedly lately. In fact I just experienced it myself!
Normally CYA degrades slowly on its own.... perhaps 5 to 10% max per month. The warmer the water the faster the breakdown. Then the only other way is via splash out and draining water and replacing with fresh.
I know I've lost water to evaporation which I've replaced with fresh but no occult leaks to speak of... one backwash this season only. So I'm as baffled as you and others? Could the CYA be defective in some way? - I dunno??

Otherwise the answers to your questions are:
1) not that I've ever heard. Not saying its not possible, but I've never heard nor read that.
2) Ditto above
3) There was one product put out on the market with the goal of lowering the too high CYA level. It contained a bacteria of some kind. Rarely worked and found by most to be a waste of cash.

Maddie

 

[pookiesunshine]

do you see earthworms in the pools? my cya deteriorated over a winter in which i had a lot of earthworms get in the pool.

 

[Southern Swimming]

Good Evening, Southern Swimming....I've heard quite a few TFP users say their CYA has petered out unexpectedly lately. In fact I just experienced it myself!
Normally CYA degrades slowly on its own.... perhaps 5 to 10% max per month. The warmer the water the faster the breakdown. Then the only other way is via splash out and draining water and replacing with fresh.
I know I've lost water to evaporation which I've replaced with fresh but no occult leaks to speak of... one backwash this season only. So I'm as baffled as you and others? Could the CYA be defective in some way? - I dunno??

Otherwise the answers to your questions are:
1) not that I've ever heard. Not saying its not possible, but I've never heard nor read that.
2) Ditto above
3) There was one product put out on the market with the goal of lowering the too high CYA level. It contained a bacteria of some kind. Rarely worked and found by most to be a waste of cash.

Maddie

Thanks for the help Maddie,
Over the last couple of years in the industry I’ve been convinced that algae blooms raise pH and was wondering if what other people’s experiences were

I’ve used the CYA lowering product and actually had pretty good success with it. I’d love to know the mechanism that lowers it to help me figure out why my CYA would zero out like that.

 

[Southern Swimming]

do you see earthworms in the pools? my cya deteriorated over a winter in which i had a lot of earthworms get in the pool.

Interesting observation but this pool hasn’t had this issue. Strange that CYA would lower during winter especially if you aren’t backwashing or replacing any water

 

[Auburn02]

do you see earthworms in the pools? my cya deteriorated over a winter in which i had a lot of earthworms get in the pool.

Did you ever get scientific backing of this theory or just an observation of your own? Because we have gotten a bunch with our heavy rains this summer, and my CYA dropped at a rate that seemed rather surprising to me, so that would be a very interesting causation if it is accurate.

 

[mknauss]

It has long been thought that the bacteria that consumes the CYA resides predominately in dirt. Typically the process starts with a zero FC for some time, then CYA converts to ammonia. If it goes the entire cycle it ends up as nitrates. Dirt being blown in or from run off or from animals entering the pool seem to be a common denominator.

 

[Newdude]

3. What other chemical interactions can neutralize CYA

Ammonia. 0 CYA and inability to hold FC at all are the 2 big red flags.

Ammonia - Further Reading

www.troublefreepool.com

To my knowledge, the only way CYA will decrease is by dilution with tap or rain water.

it also degrades on its own about 4-5ppm per month. Unnoticeable for those down south open all year but HUGE when I close my pool for 6 months and walk away from it. Between that and the off season rain I’d close every year with a CYA at 70 and be unreadably low (0-20) in the spring