I'm using a commercial temp-gun. I could make it warmer by making the substrate thinner. I spread it out thick only because i was afraid of burns. So i'll do that, and the cool end of the tank is way too cold, around 68-69 so i need to remedy that as well. Im thinking of strappin in another UTH since i have one. I'm just setting up this terrarium, it's new and a lot bigger than my last. So trial and err till i get it right. :/