Hi, am having a little problem with my temps for my beardie,hes 4 years old. Ave got a 4ft long/1ft wide/1.5ft high viv. Am currently using a 100w basking bulb (exo terra) not a coil. My basking spot is at 99f and my cool end is 78f. A cant seem to get it any higher? The probe for my thermostat is at the cool end against the side of viv. So a cant move it any further away. A was using a 150w zoo med basking bulb but the temps were to high. Example basking was 150f and cool was 80f. If a tried moving probe closer to basking spot, the light would just dim down? So ave switched back to 100w. Wondering if any1 can help? Sorry if description isint good.