Andy, this seems to be exactly where I'm at right now. I have measured CYA at 40ppm twice but I'm losing 3ppm - 5ppm of CL in the light of day - virtually nothing overnight. At 35,000 gallons, that's 3 gallons of bleach/day. No CC either right now and water is crystal clear. I got my CYA down from 100+ since last July and converted to bleach in August. Didn't have any trouble holding CL the rest of the summer - went through 1 gallon every other day to hold level required for my CYA.

But....Bleach becoming a real pain at this usage. Makes me think my pool "likes" or needs more CYA or I'm not accurate with my measurement. Will try to get pool store to test for confirmation.