Horse water tank

Bury your tank below freezing level then use a solar pump to circulate the water through a shallow trough with gravity back to the tank.

>I have these water tank that freezes
>in the winter and because I
>don't have electric power enough up
>to that area, I can't use
>the electric heater in the water.
>(the ones that you just put
>in water to keep it from
>freezing.) I was wondering if you
>have anything that could solve my
>problem. It would have to be
>something that you put in the
>water to warm up the water.
>It has 80 gallons of water.
>And needless to say something cheap!
> thanks

You can fabricate a tin box to submerge in the tank.Picture a boot shaped tin box.the toe part needs to be submerged in water and no leaks and the top part of boot is open and above the water line.make it large enough to put the base of an oil lamp or better 2 lamps in.The lamps heat the top of the toe part and keep it from freezing.It's been used for a hundred years or more.              
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                   |     |_____
                   |           |
                   |      lamp |    
                   |___________|          
About the best I can do but I hope it gives you an Idea of what I'm talking about.Any local mettle shop can make one up.