Building a rack, heat advice...

[withonor]

You can do this by using a rheostat on the front flexwatt, plugged into the thermostat controlling the rear flexwatt. However, one thing to keep in mind with having flexwatt front and rear, is that there is no where to escape the heat should a control device fail.

This is a good point and I would have to consider how often do Herpstats fail (If I use the Herpstat II which would control the front and back separately). Otherwise I would be using two separate thermostats and would have to consider the odds of two failing at the same time. I will have a unit that can control multiple temperatures or multiple units to control the different temperatures.

Considering the worst happens and both thermostats go out and I am using 24" deep tubs. It would leave 12-16" of space in the middle depending on spacing and whether 3 or 4" flexwatt was used. This is a good argument against 11" or 17".