Quote Originally Posted by mogwai View Post
you also mentioned not overdoing the stabilizer so I'll be very careful.
Just to let you know . . . there's a little bit of, well, not controversy exactly, but maybe, lack of synchronization here at PoolForum about what stabilizer levels ought to be. The instinct most experienced PoolForum members, contributors, and even moderators have is . . . get it down, if your CYA level gets near 100 ppm.

That's my fault, in large degree.

Years ago, when I began to understand the relationship between chlorine and CYA levels, the first conclusion I reached was that people needed to get their levels down, so their chlorine could be effective. When I first published the Best Guess chart around 2002, that opened up a way to function effectively even if they couldn't drain - IF they had a DPD-FAS kit and could test. But, until Richard (Chem_Geek) worked out all the analytical machinery that validated my "best guess", I didn't depend on it 100%: it WAS a guess!

And, it's only been in the last 18 - 24 months, that several other bits of analytical and historical data dropped into place, and got synched up in my thinking. The result is, some of the advice that I personally am NOW giving about CYA and chlorine levels is not the same as the advice I gave 6 years ago. But, most of the stuff written down, both here and at Trouble Free Pools is really more of the 6 year old stuff.

So . . . when you report back that your CYA level has reached 80 ppm, and you ask what you should do next, don't be surprised if some of the experienced people here tell you, "You need to drain some water, and lower that CYA level". But, that won't be what I'll tell you! What I'll say is, "Draining is an option . . . or you could just raise your chlorine level a little more, to compensate!".