Yeah, 1KW is a bit overkill even for a near 3' deep tank. Most of the day the bulbs are running at 600W. They are at 1KW for only a couple hours per day.
If I had it to do again, I'd go with the same overall power, but I'd use 400W bulbs--just more of them.
They might warranty it. I think I've had it for only 3 months. Probably worth a shot.