Hi, I wanted to mention that if 90 is the basking temp, that isn't hot enough to allow for proper digestion. The minimum for the basking spot is 95 and the maximum is 110. The cool side should be 78 to 82 with 80 being ideal. I looked at the pics of your setup and noticed that you have the stick-on round gauge thermometers stuck to your tank. If those are the only type of thermometers you're using, they can be off as much as 20 degrees. The only 2 ways to get accurate readings are with either an infrared temperature gun or a digital thermometer with a long wire & probe end. If he is spending all day in the basking spot, he probably isn't hot enough but you have to make sure that you're using an accurate thermometer so you know if you need to increase the wattages or not. What size tank is he in and what wattage basking bulbs are you using? How is his appetite and pooping schedule?
I also wanted to mention that red and black lights can disturb their sleep so if you need night heating, a ceramic heat emitter would be best, they give off heat but no light.