A few thoughts about CYA

[gordyjamz]

Thanks for the info on the bromine. I really don't have an aversion to CYA, just am curious, really. Like I said earlier, if it ain't broke don't fix it. I will probably land up going back to my current levels after the refill in spring, since it's what's been working for some years now. Though maybe a little lower on the CYA (currently at 40). Maybe shoot for 20 or 30. What did they do in the old days before CYA? Must've had to check levels every few hrs during the day, is my guess. Anyways, thanks for bearing with my inquiries and maybe crazy ideas

Ken

[CarlD]

As long as there have been Tri-chlor tablets and Di-chlor powder there has been CYA.

aylad, one of our moderators, keeps her pool at a very high CYA level, 80ppm usually, because in Louisiana, there is SUCH a high chlorine use she's be adding it 3x a day. At 80ppm, aylad maintains her chlorine between 5 and10 ppm and her pool stays clear and her chlorine usage is moderate.

This is what our "Ben's Best Guess" table is all about--correct levels of chlorine to use with various levels of CYA even up to over 100 (not recommended, but do-able).

CYA is a two-edged sword, but, with knowledge and a good test kit, you won't get cut by either edge.

This summer, lots of people around the nation have noticed much higher chlorine demand--myself included. Not sure why, but it just "is".

[waterbear]

What did they do in the old days before CYA?

Good question. Historically, anhydrous ammonia had been used to stabilize chlorine since monochloramine is more stable to UV than hypochlorous acid. Sulfamic acid and sulfamates have also been used and, if I am not mistaken, so have hydantoins and other ammonia and urea like chemicals (which include cyanuric acid and cyanurates!)

It seems that chlorine/nitrogen bond that occurs has the main stabilizing effect against loss from UV light..

[waterbear]

As long as there have been Tri-chlor tablets and Di-chlor powder there has been CYA.

The widespread use of chloinated cyanurates and the use of cyanuric acid did not really become widespread until the late 60s/early 70s but they were developed and introduced (by Monsanto if I am not mistaken) in the early 60s.

[OddJob]

Ok. I just added 4lbs of cya. I put it in an old sock and hung it in front of the return jet. I tested and the black dot was *almost* invisible at 30ppm. I'm assuming I must be close to 30 since it is a definite change from no cya to this reading.

I'm not sure why I added it now ... since I've been good all summer (just lucky?). Vacation and ChemGeek have freaked me out!!

I will post a full set of numbers after we finish swimming. And I'll have to check the chart again and adjust my bleach addition accordingly.

ChemGeek, if you happen to read this far again, do you have any thoughts as to why I made it this far (since May) without CYA and no problems? I'm not being snarky, just curious.