I want to install a UTH for Sobe. I'm tired of the bulb lowering the humidity. My hubby brought home a Exo Terra Heat Wave 8"x8" 120 volts, 8 watts. It says safe, even heat distribution. The guys at the store said it doesn't need a thermostat but I trust you guys over them. Do I need a thermostat with this thing? I know you do with flexwatt so that's why I wonder. I just started using Aspen for substrate. I don't want Sobe in any danger. Please advise. Thanks.