2800 for 12 hours seems excessive. I'm in MN so similar weather and I run my VS Pentair at about 1200 RPM most of the time. I raise it (maybe to 2000) when the pool is getting heavy use and then lower it back to 1200 after everyone leaves the pool for the day. At 1200 RPMs I'm only using 100 watts per hour. The pool has been extremely stable for over a month now, the water has been clear and I've added no chemicals to it for that month (I have a Pentair Intellichlor C40). I also have an autocover and that really helps to keep the pool clean, too.
I test the water regularly and the levels have all been very good, stable.
Also, I use 1200 RPM because that seems to be the lowest setting to keep the SWCG working. I run it at 20% most of the time and it seems to maintain the ideal level of chlorine.