I'm panning on doing a few partial drains (1-2'each time) and refill to get my cya way down. It's at well over 100 (probably 200). At what point in my refilling should I test and be at a managable level. What would a good cya level be?
My pool is about the same size as yours and I went through a similar process last year when my CYA was in the 200 range also. I drained the pool down to where there was about 9-10" of water remaining the the shallow end and then refilled it. I ended up have to do this twice to get my CYA correct. It is important to make sure that amount of water remains in the shallow end to keep the liner in place. I keep my CYA at about 55.
thanks for the response-when you did this last year, would you say you lowered it about 2 feet each drain? I worried about my liner-did you have water brought in-I'm on a well so that's what I'll have to do.