That seems to be my thought; the plans I found on the Internet used a metal tank painted black. My thought is that the plastic tanks would have a better insulating factor once the water is warmed.
Yeah, I don't think painting them is a good idea. It could chip off over time and it might make the water have a funny taste. And that could make the horses drink less - then you couldhave a case of impaction colic...
I have a question for you. Many years ago when I lived in Kansas the Vet I worked for had a solar water tank heater that he used in a rubbermaid tank. This was super handy, but I don't remember where he got it, and he passed away several years ago when I didn't need a SWH. Does anyone know of any place to purchase a Solar Water Heater for stock tanks? I even asked several of the Amish if they know where I can get one, and they don't know.
We have concrete stock tanks plumbed into the natural spring we have here. There are 6 tanks all together and as one fills, instead of spilling over it goes on to feed the next tank and so on. The last tank is plumbed to dump back into the creek. (not really relevant to the OT but I think the tanks are cool)
I have another black rubbermaid that I use in the catch pen and it's been fantastic. I haven't a clue how old it is as I got it used. It's worth its weight in gold. It's easy to clean and dump. If it's frozen a good thump will crack the ice and not damage the tank. They're 100 times easier to clean and work with.