RHP in an aquarium tank?

Has anyone every done this? If so, tell me about the set up.

I haven't but the tank would have to be fairly large or the RHP will overwhelm it. I also don't think a screen top would be sturdy enough to hold it, you'd have to make something. I'd probably use plywood that could be secured to the top of the tank.

Until my snake outgrew it, I had an 80-watt RHP in a 20-gallon tank, and it worked great. I put a piece of wood across the screen on each side to screw into and support the weight, and stuck the screws through the screen into the wood. I had to make a couple of other minor modifications to make everything fit, but it all worked very well and it wasn't difficult. The RHP covered most of the screen, which had the added benefit that I didn't have to bother to cover as much of it with foil to maintain humidity.

For what it's worth, I used the RHP just for the ambient temperature, with a UTH for a hot spot. I put the thermostat probe dangling about half an inch above the floor so it wouldn't get moved or sat on or peed on, and that maintained an even 80 degrees very nicely, even though the living room can vary from 55 degrees in the winter to over 80 in the summer. You aren't going to "overwhelm" the tank if you have a functioning thermostat.