How many racks can i run on one Thermostat?

[The Serpent Merchant]

Gonna have to disagree with that part. In my experience there's only 2 things that matter here:

1) The size and wattage of the flex watt.
2) How many watts the Tstat can support.

I have 3 racks hooked to one Tstat. All 3 are using 3 in flex watt at 10W per ft. 2 are identical AP racks. The other is a RB type rack. All are holding the same temps throughout. The total wattage for all 3 is around 350 watts which is well within the Tstat wattage limit.

It CAN be done but it isn't the safest method of regulating flexwatt. 99% of the time you won't have an issue but if 1 of the runs of flexwatt shorts out and it isn't the run that has the thermostat probe, then you could have melted tubs, dead snakes, and even a fire...