Hot climates = option of high CYA?

[joecus]

Yup, that's me! Still down here, oil slick or not

Janet

Hi Janet - I read this quote and wanted to ask you why a high cya is important to a pool that gets a lot of sunlight. That is the case with me. Also, I assume I could use the "shot glass" method to test my cya, is that correct?

[waterbear]

Hi Janet - I read this quote and wanted to ask you why a high cya is important to a pool that gets a lot of sunlight. That is the case with me. Also, I assume I could use the "shot glass" method to test my cya, is that correct?

Higher CYA can protect against loss from sunlight but you need to run the FC higher to compensate for the chlorine that becomes chemically bound to the CYA in the water and is not available as a sanitizer. Net effect in some pool is lower overall chlorine usage and in many cases chlorine does not need to be added daily to maintenance becomes less. However, all pool are differnt so YMMV.
As far as 'shot glass method' for cya, yes but it is only really useful if your CYA is testing at 100 ppm to see how MUCH over 100 ppm you are.

Since you are the third poster to post a pool problem in this thread perhaps the MODs would be kind enough to break it off into it's own thead or combine it with one of your other theads to avoid confusion!

[dhanger]

That brings up a question I've wondered about since I first started using the K2006 test kit, I've read the book that came with it from cover to cover like it was a bestseller (I'm an invertebrate, er, inveterate manual reader) and it's gratifying to see how closely the information in it correlates with most of the info here on the forum, however, on page 26, under 'Chlorine Stabilization' it states that "Above 50 ppm, only marginal stabilization benefit is observed." Some people here have said that they keep their cya much higher when they have high sun exposure. My cya level is about 45, with sun exposure at least 8 hours in summer, and I typically lose about 2.5-3.5 ppm of FC. My question then is, is that amount of loss considered high, and do people see more than 'marginal' benefit from much higher cya? I'm probably being overly analytic, but that's my nature.

Dan

[lbridges]

I have a relatively new pool (a little over two months of water). During the second month a Pentair IC-40 SWG unit was started up. Due to a miscomminication between the equipment setup guy and the company pool service the filter was cleaned not long after CYA was added. As a result the first 10 days or so I had a CYA level of about 40. The SWG had to be run at a 60% duty cycle to keep FC at the target level (set for a CYA of 70). After correcting the CYA level to 70, I have been able to turn down the IC-40 duty cycle to 25%.

This is for a pool receiving direct sunlight from dawn to dusk, space coast area of Florida.

[CarlD]

There's some discussion as to whether or not CYA levels that are higher provide any benefit. The answers seem to be:

1) If you have a SWCG, then the higher levels are mandatory (around 70) both for the correct functioning and to avoid voiding your warranty.

2) In extremely hot, muggy, sunny climes (like Louisiana) people find they just cannot keep chlorine levels consistent without higher CYA levels. Our La. Mod, aylad, finds she must always keep her pool at 70-80ppm of CYA or she cannot maintain her residual chlorine. Real experience trumps theory in this case.

In our extreme heat, here in NJ, where it's been in triple digits in both temperature and humidity (105 F and 100% humidity), despite my CYA of 50, I've been having to add LC every day.

3) It seems that if you cannot maintain a steady residual FC level, you must increase your CYA and target your residual level accordingly.

Hope this helps.

[dhanger]

CarlD-

As is sometimes the case, I know it's true that theory and practice don't always see eye to eye. Not ever having been around SWCG's I wasn't even aware of the need for higher cya for those. Interesting. It sounds as though you might be saying that higher humidity may be a factor (105 F. with 100% humidity! I salute you). Here in Phoenix we have the same temps throughout the summer, but very low humidity except for a short monsoon season, yet I have the losses I mentioned, so it doesn't seem to my mind that there is a connection with humidity. You didn't say whether the loss I am experiencing is high, low, or normal, but when you say "I've been having to add LC every day", it sounds as though it should be normal experience to maintain a steady reading for extended periods, at least longer than a day. What exactly does it mean to "maintain a steady residual FC level"? This is all fairly new to me (I've been terribly ignorant in my 5 years of pool ownership), so I'm still working on sorting out what should be normal.

Thanks,
Dan