Red light or UTH
 

the title pretty much says it all, what would you guys reccomend? I have a 20 gallon 24x12 and right now I am using a paper towel substrate though I may switch to tile. Also where should I put the heater? under the tank or under towels/ tile? thanks for any help!

UTH
 

A UTH is more appropriate for a Leopard Gecko. It is placed on the outside of the bottom of the tank on one half only, and should the appropriate size for the tank used.