Thanks so much for your help everyone!! Why do I have a feeling this is going to be a verrrry long winter! Last winter I'd be out feeding in -18 degree weather quite regularly....
Extension cords and hauling buckets. Oh this will be grand.
Well I think I'll pick up one of the floating heaters to begin with, and see if I can somehow secure it into the tank. Maybe by adding some type of covering that the floater can't get out of, but the horses can get into. Still going to be unscrewing and rolling hoses. Oh joy...