First I started hanging the Reflectix (semi-rigid bubble wrap insulation) above the pond:
Then I hung the 5w panel:
Finally I ran the wiring and connected:
I really have no way of testing the effectiveness of this system. I is pretty much just a good theory that pumping heated air underground during the day will radiate up at night. I guess I could disconnect and test the nighttime temps with and without the fan running, and maybe I will do that when it gets really cold...