Here is my system designed and worked pretty well through the summer. It is an old cat litter bucket which I fitted with plumbing parts and a toilet line to attach to the poultry fountain you see in the foreground here. I threw a tank heater in the top and closed the lid and here's my failed test. It was frozen down below in the poultry fountain. I'm sure it's because of the skinny toilet line and lack of insulation. I also knew those tank heaters only keep about a 6 inch radius un-frozen. I have pipe insulation I could wrap that tubing with, but do you think it will be enough? Let's hear your thoughts. What do you all use? Thanks in advance!