I use this: https://www.amazon.com/Pet-Products...X236_SY340_FMwebp_QL65&keywords=bucket+deicerMy DW fount has frozen entirely during nights of "just" +20F. Maybe a metal container w/horizontal nips that I can rest on a heating base during the colder nights? That might work.
So far, I have yet to see any ice in my bucket and the horizontal nipples I use are working great. I got it after I had to thaw my entire bucket when it froze solid overnight >.<
