My male ball outgrew his 20 gallon . I bought the "national geographic" 36x18x18 cage. so far I like it. I have the large zoo med UTH on one end with a thermostat but I need something for ambient air temp. What size ceramic heat emitter will work for this size of a cage? I should probably also get the 10 inch done correct? Right now I am using the came CHE I did with the 20 gal but it's not pumping out enough heat for this size cage