I just set up my tank and I think I'm going to need a second heat element.

I have a 15 gal long, glass. 3 sides and 3/4 of the top are covered in foam board (also 3 layers of tin foil on top). Newspaper on the bottom.

I have a Reptitherm UTH for 10-20 gal aquariums with a ReptiTemp 500R. There's an Accurite w/probe in the tank right now and I have a temp gun to check surface temps.

Ok. The ReptiTemp is up to the highest setting. The glass surface temp is 101. The temps on the newspaper is only 75 to 87 (91 under the hide, but it cools when I move the hide). 40% humidity.

Should I try a different substrate? A ceramic heater?

Thanks!