I slightly remember years ago I read somewhere that if the pool is calm for a while that the CYA will "float" to the top and then you can remove that water, e.g. via the skimmer, thus removing a higher concentration of CYA. Also I believe that the article/post/whatever it was suggested siphoning off the top while having a water hose in the bottom of the pool slowly adding water and "pushing" the higher concentration CYA water towards the siphon.

About a year ago a co-worker told me a pool store guy verified the idea that the CYA will stratify in a calm pool and that to remove the most CYA let the pool settle and then remove the water from the top.

I have been meaning to test my water with the pump running for the "normal" cya level and then after letting the pool sit overnight test the water from a couple inches and then a couple of feet down to see if there is any difference.

Anybody else hear anything similar to this?