Solar powered stock tank deicer?

I couldn't figure out if there was a better spot for this question or not.

I need a way to keep stock water tank ice free without electricity.
Is there something out there on the matket? Has anyone made something that works for them?

I am in BC Canada. Our winters here average -15Celseus in winter. But do drop as low as -30.

Any help or suggestions would be greatly appreciated. I have never used solar past an electric fence charger before so I don't know where to start to built from scratch.
Jaime

You are attacking the problem from the wrong end: literally. Most farmers do not keep their stock tanks deiced via solar, but rather geothermal, but do not let the name scare you. All it takes is to buy a culvert (steel or plastic) as big as possible, and longer then your frost depth. For me here in Maine, that is 4 feet, so I need a culvert that is 5 feet deep.

That culvert gets buried VERTICALLY into the soil so that the heat (57 degrees here in Maine below the frost line) rises up and hits the underside of the stocktank. By insulating your stocktank, and making the surface area smaller so that water is not as vulnerable to the cold, no ice forms.

If you do searches for this, you will find a host of designs online. In fact I found one from Alberta, but it was done with Mining Truck Tires buried in layers, but it is the same idea.