with a pool that gets all-day sun, a solar cover is very helpful in decreasing the chlorine demand. my cover doesn't do a whole lot to warm the pool in the summer - in fact it warms up more during the day with the cover off - but it probably cuts my chlorine usage in half. (for the record, the solar cover holds in the heat at night far better than it generates heat during the day. which has nothing to do with what you asked...)

anyhow, when i was using 6% bleach in my 24,000 gallon pool, with the solar cover on when the pool wasn't in use, i was putting in 48 oz. each night and that would keep me at a pretty consistent 2 - 2.5 PPM. i had to use twice that over periods when i got too lazy to haul the cover on and off.