Yeah I see what you mean. It is a bit too risky...
It sucks that I can't keep the cool side warm enough. I'm basically going to need two thermostats per snake now. I have two of them in different sized tubs. I had originally hoped to just have everything off one thermostat, but I'm finding tub size has an effect on temps, even though all my flexwatt is the same size and plugged into the same thermostat. Only if I use the same tub size positioned in the same way do I get the same temps.
Surely I'm not the only person in the world with a house heated to 72 degrees that houses their snake in a tub exposed to the open air. Are there any other options other than a 2nd heating source? Maybe I need to look into insulation for my tub. I also thought about stacking the smaller tub on top of the larger. I'm hoping some of the heat from the smaller tub will carry down the larger tub's cool end down below, and vice versa.