Article on CYA--Comments?

Interesting information. Can't vouch for its accuracy.

Summary: Most of the benefit of CYA can be realized at 5 to 10ppm as far as chlorine staying power. ORP of any chlorine level above 1.2 ppm is about the same once CYA exceeds 70ppm. Direct relationship between ORP and disinfecting action isn't fully quantified. Some bacteria in controlled conditions took 100 times longer to die in CYA stabilized water, although others MAY have been more quickly killed in the presence of CYA.

http://www.strancoaquatics.com/lit_f...ilization1.pdf

And another. One seems to be derivative of the other:

http://www.ppoa.org/pdfs/PrP_Cyanuri...0or%20Bomb.pdf

Those were very interesting reads, thanks.

Interesting, but, it seems to lack the most important and practical everyday info that would help to determine what level of CYA you wanted to maintain.
ie: Given summertime 8-10 hrs of sun, high temperatures of 90 degrees, a CYA level of 10 ppm, FC level of 2 ppm in the morning, what will my CL level be after 24 hrs? 48 hrs? 1 week? How often and how much CL would I need to add to maintain CL @ 1- 2 ppm? (Or, in my case, how much higher would I need to set my SWCG to maintain a constant CL level?) I would certainly be willing to try a lower CYA level but given my present reading of 60 ppm and our near drought conditions, it will be a long time before I pump enough excess water out of the pool to drop my CYA significantly. Maybe someone who is just opening their pool with a near zero level of CYA would be willing to try very little CYA and report their experiences.

Quote:

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Originally Posted by JohnT

Interesting information. Can't vouch for its accuracy.

Summary: Most of the benefit of CYA can be realized at 5 to 10ppm as far as chlorine staying power. ORP of any chlorine level above 1.2 ppm is about the same once CYA exceeds 70ppm. Direct relationship between ORP and disinfecting action isn't fully quantified. Some bacteria in controlled conditions took 100 times longer to die in CYA stabilized water, although others MAY have been more quickly killed in the presence of CYA.

http://www.strancoaquatics.com/lit_f...ilization1.pdf

And another. One seems to be derivative of the other:

http://www.ppoa.org/pdfs/PrP_Cyanuri...0or%20Bomb.pdf

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I'm aware of the PPOA article, but hadn't seen the earlier Stranco article. But, I'm glad to have additional confirmation of what I've said previously about this information. But, in order to understand why the article takes the position it does, you need some background information.

Kent Williams created the PPOA (Professional Pool Operator's Association) 8 or 9 years ago as a for profit vehicle for his consulting business. I was on his mailing list, when he started up, and even briefly had a paid subscription to his "Pumproom Press" newsletter. But, I cut all ties, after I found how tightly connected to Stranco he was, and even more so, that he alone controlled and profited from the PPOA.

Now there's nothing wrong with having a business and trying to make a profit. (I'm definitely trying to make the PoolForum profitable, so far without any real success, but I'm still trying.) What stuck in my craw then, and still does now, is that Kent went to considerable lengths to make the PPOA look like a public interest foundation that was either legally, or practically, non-profit when privately his intentions were entirely different.

The other issue was his effort to create an aura of independence from industry control, when in fact, he maintained very close ties to Stranco, his long time employer.

These latter ties are signficant, because Stranco's business was, and is, the use of ORP sensing to build swimming pool chemical controls for large swimming pools. Now like most salesmen, Stranco's salemen didn't like to see weaknesses in their product line which resulted in reduced sales. But, there is a huge weakness in ORP based pool control. Stanco and others have worked for years, without notable sucess, to try to produce a sensor that would actually, and reliably, sense chlorine levels. Their lack of success has left them dependent on ORP sensors. And that was a problem.

The full explanation is much too complex to get into here, plus, I don't fully understand it myself, though I think I've pieced as much of it together as anyone. But the short version is that, while ORP sensors can be used pretty effectively to control chlorine on pools with no stabilizer, high stabilizer levels (ie, more than 10 ppm) complicate ORP control enormously. And, on outdoor fully stabilized pools, ORP control of chlorine is virtually impossible. I learned that for myself, the hard way -- I sold ORP controllers to a number of my commercial customers.

So, Stranco's salesmen were stuck.

They could either admit to all the Parks and Recreation Departments who inquired about their "pool automation systems" that the Stranco systems really only worked well indoors. Or, they could 'solve the problem', by eliminating stabilizer.

But, how to do that? After all stabilizer was making it easier and cheaper to operate outdoor pools, by making the chlorine residual more stable in the pools, thus eliminating sanitation 'dead' spots, in the center of pools, at the ends of long slides and so forth, where the sun had stripped all the chlorine from the water.

Well, there was a way. What if, instead of considering the chlorine level as the standard of sanitation, they were to argue that ORP was the REAL stuff, and that chlorine only counted, if the ORP was high enough. Then, since CYA lowers the ORP value for any given level of chlorine, they could argue that CYA was making chlorine dangerously ineffective.

What's more, there was some support for doing so, from an obscure WHO (World Health Organization) guide that suggested the use of ORP, under certain conditions, as a marker for adequate sanitation of drinking water. Woohoo! The UN says that ORP is the right way! Let's go tell everybody!

And they did.

Now, Stranco hasn't been the most vocal or deceptive player in this game. That honor would go to Jacques Steininger of Chemtrol, a much smaller maker of ORP controllers. But Stranco played too. And arguably, they played better.

Now, I can't prove that Kent is deliberately and knowingly 'shilling' for Stranco. I can't even prove that he deliberately set out to deceive the PPOA's 'members' about the nature of his organization.

But I can tell you that I'm very suspicious, and that his arguments seem to me to have far more to do with Stranco's and his financial interests, than what's best for you or other pool owners.

-- There's more, but I've run out of time for the moment and will have to get back to this. --

Ben
"PoolDoc"



Additional info:

from the PPOA website:
"Rob Kappel of US Filter Stranco Products has been named the president of the PPOA Board of Directors."

Ben, is your problem with this the conclusions about CYA or the effect on ORP? Much of what it says about CYA seems at my "first glance" to fit with your ideas. Is it just their spin that skews the results?

I've been discussing these issues with a friend who won't take my crystal clear pool on opening as evidence that I'm doing anything right. He also won't accept his annual battles with algae at opening and in mid-summer as evidence his 100+ CYA is an issue. That's why I've been stumbling across this stuff. Thanks for your input.

Ben,
It might be useful to explain what ORP is REALLY measuring and how that relates to sanitation acitvity (although that discussion might be better suited to the "China Shop":)