Good read on CYA

I was looking for something else and ran across this-

http://www.dsf.health.state.pa.us/he...a=180&q=234664

A good write up on CYA I thought some would find helpful.

That looks great...except for the "cyanuric acid is never used up" line...we've got several on this group that have proven that wrong after a major algae outbreak over the winter. And Ben has backed that up with an explanation of "why/how" the cyanuric acid is used up that way.

Very interesting. The descriptions of CYA, Tri-Chlor and Di-Chlor are great, as is the explanation of why not to use it in an indoor pool.

But when they get to maximum and excess amounts there are problems.
Both points 4 and 8 are simply not accurate, and point 7 is misleading.
If you maintain a CYA of 30-50, you should NOT maintain a FC of 2ppm, but at least 3ppm. As CYA goes higner, you need higher minimum FC levels.

There's nothing unsafe about CYA in the 80-100ppm range. You simply need more chlorine. While it's true that CYA has diminishing returns as it rises, you can ALWAYS raise the level of chlorine enough to compensate.

Hidden in this article is the TEKTAT ("Things everybody knows That are true" but aren't) that chlorine should never be above 3ppm, which is nonsense.

All good points.

I caught those when I read them, but I was searching for something else so I copy and pasted the url in word, to add here later. I planned to add a disclaimer of sorts, but forgot :(

If you check the referecnes in the article they are both from things written by Kent Williams. Ben has referred to his CYA-Benifactor or Bomb article in another post. You might want to read it!
http://www.poolforum.com/pf2/showthr...=Kent+Williams