Our true coolers are set up with a false wall in the back to cover the 30 inches of 11x12 heat tape.
We use a bathroom ceiling fan plugged into a rheostat on the floor of the inc, it sucks air into the fan and blows it through a hole in the false wall.
The air is pushed over the heat tape and heated as it goes to the top and out into the main area to be sucked down and repeated by the fan.
Super stable, no worries about getting the tubs too close to the heat tape, and hot spots are a thing of the past.