I am having trouble keeping a temperature over 65 degrees in a Extra Large Tortoise (Dog) Igloo. I have a 5 year old Sulcata and a 7 year old Sulcate. I have a 500 Watt temperature Controller and a 150 W Heating Emitter, however it is still getting below 65 in the Igloo on the cooler nights here in Los Angeles. Anybody have recommendations how I can keep the heat up? The Igloo does not have a door. I have thick plastic Carpet runner slit vertically to allow them to go in and out, but there is a draft. Any suggestions?