You can not use generic third party probes with the Smartfire BBQ Controller. Worst case it may cause electrical damage to the unit.
Probes are made differently between vendors and products - ie generic third party probes will not work. Thermistor probes are rated on a base resistance at room temperature (25C) and companies use a range of base ratings, we chose 1M Ohm as it provides better granularity in temperature readings across the key BBQ temperature range (100-400F), whereas low resistance probes designed for weather and traditional cooking (0F to 200F) lose that granularity. On top of that, different manufacturers use different non linear response curves.