Umualet

So I'm preparing a tank for a hatchling Western Hognose. I'm getting ZooMed Under Tank Heater (U.T.H.) and curious if that would heat the glass tank of an Exo Terra Small Wide 18"x18"x18" tank enough for a heat gradient. I don't plan on using any heat lamps, just a day and night cycle.

I originally bought the 4"x5" heat pad for the small plastic Kritter Keeper I'm keeping the hatchling in because I heard they have trouble with large spaces.