hey i just got a t5 repti sun 10 bulb and 100 watt bulb to replace my solar glo mvb bulb in a 40 gallon tank. they are placed next to each other. it seems that hes not warm enough yet because he hadnt pooped or ate very much today. is he just getting use to the new lights?
He may not be warm enough, but the best way to tell is by measuring the temperature with either a digital thermometer with a probe directly on the basking spot or a temperature gun.
What are the temp readings through the tank? If you suspect impaction you could drop some baby food applesauce or pumpkin on his nose with a drop or two of olive oil to help things along.
100 is OK for an older dragon. I'd try bumping it to 105 or so for a younger one by moving the basking spot just a little bit higher. What do you have on the cool side? 75-80? If so then that's a pretty decent gradient and probably won't cause much problem.
I'd start tracking his weight. It's possible that he's getting used to the lights or going into some level of brumation but if that's the case his weight should remain stable. If his weight is dropping then it could indicate a health problem.