Larry,
Glad to see someone active on this forum. Carl is obviously right with the two speed pump idea and with rates 3X at peak I'd certainly be thinking of innovative ways to cut power consumption too. I don't use a chlorine generator and have no experience with them but I would see nothing wrong with letting the chlorine level bounce around a bit. Jack it up at night and let it fall during the day. With the right CYA level the daytime drop should be easily manageable. Not like you have no CYA and all the chlorine disappears in an hour. Your concerns about the solar blanket efficiency and gradients without circulation are valid. I don't think the efficiency will be an issue because even with stratified water, hot right under the surface and against the bottom side of the blanket, there is still a lot of heat transfer from both the heating of the cover and infrared penetration. The temperature differential is the key to heat transfer. Simplistically, consider laying the cover on dry ground and see hot hot it gets....plenty. Compare this to the water temp just under and if the water is 80 or 95 the differential will still be very high. Of course a 2-speed pump would eliminate these issues. As for quieting the pump, since you already have a shed there are cheap tricks to shut it up a lot. Mounting the pump on a vibration insulating board, connecting the pipes with radiator hose to cut down noise conduction, and maybe even another ventilated and insulated pump box cover. I can point you to the right threads if you want to pursue this.
Hope this helps.
Al