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Thread: Interesting CYA Article

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    Interesting CYA Article

    I have been very interested on CYA and Chlorine relationship since reading on forums about it posted on here. Through my readings I have begun to see that it can be your best friend and can also be your worse nightmare in pool water if allowed to get out of hand. I am not sure if anyone has read this article that has a lot more knowledge in this topic than I, but thought I'd share it. It's called ("Cyanurics ~Benefactor or bomb?"
    by Kent Williams, Executive Director of the Professional Pool Operators of America.) Here is the link http://www.ppoa.org/pdfs/PrP_Cyanuri...0or%20Bomb.pdf

    One of the things I got out of the article was that a need of 5 to 10 ppm of CYA is all is needed to achieve the needed protection from ultraviolet rays. I also concluded that even at a level of 70 ppm CYA, UV protection is generally the same as if it were at the 5 to 10 ppm level. But with increase in CYA above 70 or so ppm comes a big drop in the effective use of residual chlorine that is in the swimming pool. If I have misinterpreted this information, I am all ears to hear from the experts. I trust the expert advice of you guys here. Just thought this was a very good article and would love to get some input from others. This topic is very interesting to me and could possibly help save some money in the long run.

    Thanks and hope this the proper forum for this site,

    Al

    Edited by moderator to fix url tags
    Mountain View, Arkansas, 23,000 gallon in-ground concrete pool with a 24-in Hayward Pro-Series Sand Filter with side-mount. Chlorinator is attached but only use occasionally and a 1 hp pump.

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    Richard320's Avatar
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    Re: Interesting CYA Article

    Quote Originally Posted by ac130loadmaster
    I have been very interested on CYA and Chlorine relationship since reading on forums about it posted on here. Through my readings I have begun to see that it can be your best friend and can also be your worse nightmare in pool water if allowed to get out of hand. I am not sure if anyone has read this article that has a lot more knowledge in this topic than I, but thought I'd share it. It's called ("Cyanurics ~Benefactor or bomb?"
    by Kent Williams, Executive Director of the Professional Pool Operators of America.) Here is the link [url]http://www.ppoa.org/pdfs/PrP_Cyanurics%20-%20Benefactor%20or%20Bomb.pdf

    One of the things I got out of the article was that a need of 5 to 10 ppm of CYA is all is needed to achieve the needed protection from ultraviolet rays. I also concluded that even at a level of 70 ppm CYA, UV protection is generally the same as if it were at the 5 to 10 ppm level. But with increase in CYA above 70 or so ppm comes a big drop in the effective use of residual chlorine that is in the swimming pool. If I have misinterpreted this information, I am all ears to hear from the experts. I trust the expert advice of you guys here. Just thought this was a very good article and would love to get some input from others. This topic is very interesting to me and could possibly help save some money in the long run.

    Thanks and hope this the proper forum for this site,

    Al
    Now we wait for Chemgeek......

    I skimmed the article, and saw the graph, so I see where you're getting data. This ought to be interesting. I did note that the article is from 1997, so more research may have been done since. Now we wait.

    I'll also wager that this thread gets moved to The Deep End
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    Mod Squad JohnT's Avatar
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    Re: Interesting CYA Article

    Check out the discussion Here

    Good bet on The Deep End move Richard.

    Just as an FYI, the reason topics like this go to The Deep End is to try to avoid intimidating new folks with details they really don't need to worry about at first.
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    JasonLion's Avatar
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    Re: Interesting CYA Article

    Quote Originally Posted by ac130loadmaster
    One of the things I got out of the article was that a need of 5 to 10 ppm of CYA is all is needed to achieve the needed protection from ultraviolet rays. I also concluded that even at a level of 70 ppm CYA, UV protection is generally the same as if it were at the 5 to 10 ppm level. But with increase in CYA above 70 or so ppm comes a big drop in the effective use of residual chlorine that is in the swimming pool.
    As mentioned in the topic JohnT linked to, that article is a mixture of good information, bad information, and information that while correct is misleading.

    CYA at 5 does give significant UV protection. CYA at 50 gives more UV protection. CYA at 80 gives even more UV protection. So that sentence is true, but misleading, higher CYA levels help more, and more protection is worth something.

    Likewise, as you raise the CYA level, the effectiveness of a fixed FC level declines. But there is no sudden drop off in effectiveness. If you control the FC level so that it is always a fixed percentage of the CYA level the effectiveness of the chlorine remains more or less constant over a very wide range of CYA levels
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    Re: Interesting CYA Article

    The Professional Pool Operators of America (PPOA) is mostly focused on commercial/public pools and waterparks. These generally have a high bather load where most of the chlorine usage comes from oxidizing bather waste. In such an environment, there is very little benefit seen to having more than 20-30 ppm CYA since the savings in chlorine from reduced loss in sunlight pales in comparison with the amount of chlorine needed to handle the high bather load.

    Residential pools are generally a much lower bather load where the bulk of the chlorine loss is due to breakdown from sunlight. So in this situation, a higher CYA level shows a much more significant benefit, even at 80 ppm or 100 ppm though high CYA levels are trickier to manage since shock levels of chlorine can become impractical. Nevertheless, there are many residential pool owners with saltwater chlorine generator (SWG) systems that operate their pools at 80 ppm and there are some pool services that maintain pools with 100 ppm CYA successfully (without use of algaecides, etc.).

    I've written to Kent Williams at PPOA over the years and have never received a response -- ever.
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    Re: Interesting CYA Article

    I really appreciate all the responses because it really has helped me have a better understanding. This may be a dumb question or I may be missing the answer somewhere, but if the CYA is higher then doesn't it require a higher FC level to maintain effectiveness of the chlorine? If I am keeping my CYA at 20 ppm, then the chart says that min FC is 2, max FC is 3 and shock level is 10. So why would I want to keep my CYA level higher if it is going to require me to keep a higher FC and shock level to maintain the same effectiveness? ie, CYA level 50 ppm will increase my chlorine use to maintain a min FC of 4, a max FC of 6 and shock level of 20. Would I be saving on chlorine use by keeping pool stabilization at a lower level? Sorry if this seems like a repeat question, I just guess I'm not understanding the benefits of keeping a CYA level of 50 or 60 versus a level of 10 or 20.

    Thanks.

    Al
    Mountain View, Arkansas, 23,000 gallon in-ground concrete pool with a 24-in Hayward Pro-Series Sand Filter with side-mount. Chlorinator is attached but only use occasionally and a 1 hp pump.

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    JasonLion's Avatar
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    Re: Interesting CYA Article

    Higher CYA levels in a residential pool mean less total chlorine usage, even though you need to maintain a higher FC level. In a "typical" residential pool with CYA at 30 you might use 2 or 3 ppm of chlorine per sunny day. In a pool with CYA around 80 you might use 0.5 or 1 ppm of chlorine per sunny day. There are tradeoffs, more CYA isn't universally better, but more CYA does save chlorine in routine day to day usage.
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    Re: Interesting CYA Article

    That clarifies it pretty good. I have learned a lot in a couple weeks of reading on this site and am continuing to learn as much as I can here. Thanks again for all the help from everyone.
    Mountain View, Arkansas, 23,000 gallon in-ground concrete pool with a 24-in Hayward Pro-Series Sand Filter with side-mount. Chlorinator is attached but only use occasionally and a 1 hp pump.

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