Will this work?

[swimmer]

I have a two gallon plastic waterer, the one with a red base. Can I flip a plastic heated dog dish to put under the 2 gallon waterer to keep the water from freezing? Has anyone tried this? The plastic dog dish I bought from Wal Mart. I used it last year, but the water got pretty messy. Just wondering if the dog dish need water in it to heat up. Let me know your thoughts. Otherwise I'll attempt the cookie tin heated base. Or any other heated base that someone wants to suggest.