Tubs directly on flexwatt?

[yeroc1982]

In my opinion, it is better to mount your flexwatt to a piece of plastic the same thickness as your tub, and then mount the plastic to the thermostat. This will give you a better idea of the temp inside the tub, not the temp of the actual flexwatt. If you mount it directly to the flexwatt, the thermostat will turn off quickly, because the flexwatt heats up quickly.

If I can find a piece I will do it. Makes sense.