Neighbors got me these great De-Icers for my 50 gal horse troughs. FarmInnovators.com is the company. They got me the Model C-500. All I had to do was put them on a cinder block in the bottom of the troughs and plugged them in. It was 18 with a windchill of 8 this morning in my area. Two nights in a row no ice. I unplugged around 10 am yesterday and plugged up at 11 pm last night, with a little ice layer. Work well. They apparently have tons of models to chose from.