I have full sun on the pool from 9:30am until 7:00pm for most of the summer months. It was a little lower consumption on cloudy days, and I never had my pool covered last year (solar cover delaminated over winter).

I carried 40-50 ppm CYA - and it drifted from around 3-4 ppm after adding the bleach to .5 to 1 ppm in the evenings.

I was surprised about the speed of the loss as well, but I never had any CC in my pool last year - and the waster was crystal clear all year long.