Or you can just get a herpstat with a built in fail safe ;-). RBI has great racks and their turn around time is unmatched. I ordered 3 racks on a Tuesday late night, and received them on Saturday morning following. Boaphile (Rhinoraxx) have a decent to long wait time on producing / shipping their rack systems. Something to keep in mind. If you are going for the CB70 rack, just stick with RBI, rich will make sure you're good to go. I have a stack 3 high, ran on a herpstat 1 using dimmer mode, and my heat tape stays at about 34% to keep the heat tape at a reading of 106, and the tubs at a reading of 91-92 varying on tub to tub. Make sure you get an IR temp gun to go with your new rack. It will be your best friend with your thermostat.