Heat Tape does nothing for ambient in a cold room. You need to rethink this set-up for your house conditions bro. You need a CHE and the UTH for your hot side.. Ditch the homemade rack idea for 1 tub. Use the heat tape now to keep him warm under his Hide and get yourself a 20 long tank this weekend so your CHE goes over the top on the cool side, uth on the hot side. Make it easy on yourself.