I use a 25W blue light during the day just to keep the ambient temp on one side since I live in a hot area, we always have our A/C and fan on, but he's usually just in his hide. The light hangs over the cage so no contact with it or the dome. Then a UTH at night with a thermostat / probe regulating the temp. We noticed the first patch and the spot on his head the day we got him.