I have been trying to figure out what gauge to install/use myself. If you can use temperature indicating tape (which I couldn't seem to find online), can you use a laser temperature gauge as well? I have pretty easy access to my tanks so this wouldn't be a problem. Could you use the temperature gauge for steel gas tanks as well?The air above the liquid is generally warmer than the liquid. I even know a fellow that has temperature indicating tape on the the side of the tank. It works amazingly well, for a few-dollar solution.