measure temps of flexwatt or temps inside tub?

[Street Killer]

You need to be concerned with the the temp of the floor of the tub were the flex-watt is located. This is were the hot spot is and were you need the control to avoid it for getting to hot. Have you considered a thermostat rather than a rheostat to run the rack. It is going to be very tough to control the hot spots in the other tubs with fluctuations in ambient room temps and the natural vertical thermal gradient that happens in racks (warm air rises). A thermostat goes so much further in helping maintain safe ideal conditions rather than a rheostat. I understand rheostat are cheaper and can be made of under 10 bucks, but I have issue with rheostats as I think they open the door to cooked snakes. Just my 2 cents

Chuck

i've been keeping a close eye on the temps and there is not much fluctuation with the rheostat. but yes, i will eventually get a thermostat... soon.