Well, what type of enclosure is it? I really didn't get that. If its a glass tank you might consider a "versa top" which is a folding glass top for tanks. It can help with both ambient temp and humidity. a 100w heat bulb is kind of high. IMO, I would forget about going to a 150w bulb, and concentrate on another method. Check the uth and make sure it's on a thermostat and functioning appropriately. Maybe consider a ultratherm as a replacement because the mechanism for heat transfer is a bit different. Ultratherms are more efficient than standard uths. Peace. Good luck.![]()