If you're thinking about getting one of these I highly recommend it. I am not a sponsor of Nelson Manufacturing. I am a customer. I have fought large tanks of water for livestock for over 20 years. Why didn't I get a couple of these sooner? If you purchase one of these I promise you would be satisfied. No worry no frustrations, just use it. No scum. No bugs. No algae in the summer. No evaporation in the summer. No evaporation in the winter. Never ice. The heater is automatic. It comes on when needed controlled by a thermostat. The heater is 250 watt as opposed to a regular tank heater which is 1200 to 1500 watts. I think over the years I've probably spent $400 on tank heaters. That's nearly the price of a Nelson Manufacturing livestock waterer. It also uses geothermal which cuts down on heater use. The water is filtered and your livestock will always have clean fresh water.
The company has excellent support. Even after the sale you will receive excellent support. Also to my surprise, the owner's manual has a great troubleshooting area and tells you how to diagnose problems if they occur. They tell you how to test the thermostat and the heater too. They tell you how to fine-tune your system so it works flawlessly and trouble free. You don't find that kind of support and product anymore.
It's really quite a simple system and they've been making these since 1947.