Has anyone tried using a pond pump or aerator in their water tank to keep it from freezing? We have no electricity in our barn, and so cannot use a tank heater. Have seen "solar stock tanks", but they are much more permanent than we'd like. I was thinking that a small solar set-up with a 12v pond pump or aerator might work. It has to be done on the cheap, because we're a Non-Prof, and I'll pay for experiments like this out of my own pocket! I'd be open to other thoughts, too!