Temps

I have asked this in the past and I,am still having problems.All tubs are the same size all in the same rack all using the same size and make of flexwatt all on the same thermostat.Still getting different temps. the lower racks are hotter and since heat rises I would think if tubs were going to be hotter it would be the upper tubs.Also the probe is on the middle rack directly on the flexwatt.
Thanks.Mike.

That's a tough one Mike. It almost seems as if the lower tubs are closer to the power supply and somehow the further you get from the plug the less power you have. It sounds like a minor short.