Yea with the situation you got there isnt much you can do... You can do a space heater and have it near the tubs to put some warmth near the rack... maybe even try a CHE pointing towards the bottom of the tub since the heat will rise... I was in the same situation last winter when I was usuing glass and I had to use a CHE with each tank... that got expensive real quick and the electric bill went skyrocketing... Now I have them in a room where I can keep the temps above 76 at all times... How cold is it getting in there? I allow my night temps to drop to 77 and have had no problems. Best of luck... Hopefully ur little idea will work out for ya.