CYA consumption

[bkfamily1]

Is there anything other than algae that consumes CYA. I have added enough CYA to have raised the CYA 80+ ppm (21 pounds in 30,000 gallons), and I am still below 40. I have not had a single algae outbreak, and everything has looked good all season. I jus can't figure out why the CYA is not coming up and starting up.

Thoughts, anyone?

Thanks

 

[BestJoeyEver]

First off, algae does not "consume' cya. Nothing consumes it. the only thing that lowers it is draining and slash out. (It does break down naturally but its a couple ppm per month) . FC is what is consumed by algae.

So a couple things to consider:
How did you add the CYA? In a sock, hanging in front of a return? If you just sprinkled it in, it's gonna take a long time to dissolve.

How long ago did you add it. For some reason when I add CYA to my pool, it doesn't seem to register in the test for a couple days. I've read where some people say it's right away, but that's not my experience. So maybe you just need to wait.

Lastly, how confident are you that you're testing correctly? The others here will tell you 'back to the sun, bright day, quick glances, waste high'. All good advice. Personally, when I test, I fill to the 90 line, then glance, then fill to the 80 line, then glance, the keep going until I don't immediately see the dot when I glance. I find if I stare right at it then I can always see it. I can't remember who posted that method, but I find it most reliable.

So l the me know about those first two questions (when and how).

 

[Perpetual summer]

Bk, hey, I am west of you in Valley city. I lost some cya a month or so ago due to heavy rain and draining a couple inches of water out of pool. I believe you guys have gotten more rain than we did. Have you drained some water? Its one way for cya loss.

 

[Akathisia]

...The others here will tell you 'back to the sun, bright day, quick glances, waste high'. All good advice. Personally, when I test, I fill to the 90 line, then glance, then fill to the 80 line, then glance, the keep going until I don't immediately see the dot when I glance. I find if I stare right at it then I can always see it. I can't remember who posted that method, but I find it most reliable...

That's the way that has been working most consistently for me too. Verified with a 50 ppm standard from TFTestkits.

 

[bkfamily1]

Joey

Thanks for your input.

I add the stabilizer in a sock put inside the skimmer. I have been doing that for quite some time and it has always worked well. I always wait a week to check my stabilizer level after an addition. So I am confident that my addition methods and testing regimen are good.

I am also confident in my testing accuracy. Eye test using the method you described, specifically glancing at the dock. That has always yielded repeatable results. Historically I have always been able to get a reliable response from the testing when I add stabilizer.

I do not recall the chemical mechanism, but if you get an algae bloom it can break down the stabilizer in some manner. Perhaps I did not phrase it well when I said algae consumes stabilizer.

I did not think there was any other way to lose stabilizer, other than the things you mentioned, namely splash out or draining. But this year something is impeding my ability to bring up the stabilizer level. I am hoping a discussion here might help me find some ideas. If not, I will just keep adding, and I am sure it will eventually get where I wanted to be.

 

[Texas Splash]

An algae outbreak itself should not have much effect on CYA unless there was a lot of backwashing during the SLAM to remove the algae. For those who close in the winter and re-open with low to no FC, there can be a chemical transformation with the CYA that converts to ammonia. In that case, the ammonia simply eats-up everything. But I don't suspect that's what you are experiencing. If you are confident with your testing, then I would attribute CYA loss to one of the following:
- Water exchange, either on purpose (backwashing) or from lots of rain and overflow
- A bad batch of stabilizer. It's happened on occasion. Last year I bounced back & forth between a couple different brands because I wasn't seeing the results I expected. Not sure if it was a bad batch/lot, but something weird was happening.
- Normal CYA consumption of about 3-5 ppm

For what it's worth, the old advice about waiting a full week to re-test CYA isn't necessary. Once the granule stabilizer is fully dissolved from the sock, it should be very close to reaching the new CYA goal in about a day or two. Hope that helps.

 

[AUSpool]

A bit of light reading.

Degradation of Cyanuric Acid (CYA))

 

[bkfamily1]

Texas Splash, thanks for reminding me of the bacteria mechanism. I remembered reading about how CYA disappears over the winter, but thought it was algae. I did not recall it was bacteria. Thanks also for the "bad batch" thought. That may well be what it is. I bought an unusual brand of CYA from a place I do not usually use.

AUSpool, thanks for the link. Interesting stuff.

I guess I will just keep dosing and ride it out. It really isn't causing any problems.