Thanks Reinz. I don't have the IR bulbs inside the cages. Those are LED lights you see in the enclosures. I have 8 in circle screens on each enclosure and I put the IR bulbs on top. My bull snakes are in the bottom two enclosures and my kings are in the top one. The bulls don't really need much heat so UTH's work just fine for them. I use the ultratherm uth's also. Sometimes I'll put the IR bulbs on top to boost the kings and carpets ambient temps, especially during the colder months. I feel you on getting that herpstat 4. I might have to add one of those as well.