I have noticed that one local bulk supplier has painted their above ground storage tanks black. In the summer around here, I imagine the temp of whatever is stored in them is substantial. I have wondered if it was to take advantage of thermal expansion to increase bulk. If they are selling tens of thousands of gallons annually, I wonder if there is any meaningful profit to be gained. Seems that loss due to evaporation would be significant in that situation. Unless, they have some kind of vapor recovery system.