I'm having the same issue. I was considering getting a thermostat but if I'm going to make the investment, I want it to control multiple heat sources (tubs, incubators, etc.), and the only way to do that is to pay $200-$300+ for the Herpstat II or Herpstat Pro. I might go with the Herpstat II once I build my rack. I can wire all the flexwatt into that and use one probe there, and have another probe for my incubator.

v