HCA: Hermit Crab Association

Hey all, I'm building a crabitat for some hermies I have yet to get. I'm very excited. I'm trying to figure out if I should put UTH(s) on the back wall or the side walls... I have a 12"x24" 20gal glass tank that I plan to use an electric fogger with. If possible, I would prefer to put the UTHs on the short walls, but I don't know if it would provide enough heat.

Thanks for the help!

Also, I'm new to crabbing, so any and all advice would be appreciated.

It is going to depend on a few factors, including what your room temperature is. I have my tank in a room where the temperature varies greatly between seasons. So for me, I have two UTH on the back and one on each side. I can plug them in and unplug them as needed to keep the temp where I need it.
Most people put one UTH across the entire back of the tank. If you are worried about it heating the tank up too much, you can put it on a thermostat.

I was planning on using a thermometer anyway, so I guess I'll try with both short sides and report back when I can. If it's not warm enough I'll also get a third. Thanks!