They make a buried concrete tank that you can insulate real well so that you cut down on freezing as much, then the drill a pin hole in a piece of copper tubing that comes off the supply line from the pond, will keep the surface moving enough to keep it from freezing.
Remember to have the supply line coming from the pond coming from a deeper elevation so the water isn't quite as cold, also the lower the tank is below the pond elevation the more pressure you will have coming out of the pin hole to achieve more water movement at the surface.
The tank is designed that the upper water level has a overflow going out the back again and we install a drain to carry that water way away from the tank area to keep it from creating a mud hole right in front of the tank.
I know this doesn't have the recovery option to put the water back in the pond like you prefer, but it can be shut off so that you only use it during really cold spells, thereby minimizing your water losses, usually we receive enough spring rains to restore the losses.
I have installed several of these for customers and for the most part they seem to be happy with them.
The eternal frost free, off grid, no power, cattle waterer, that is foolproof is the dream of every cattle rancher out there. Maybe I will invent one someday, Id be rich.
