Quote Originally Posted by dr del View Post
Hi,

Is the thermostat probe sitting right on the UTH?

Possibly taping it down tight might help - and have you double checked the thermostat by turning it the other way? (preferrably with no animal in the tank just in case ).

If the 500R a dimmer type or an on/off type - I can't remember at the moment.


dr del
He's using the rheostat, not the 500r thermostat.
I've heard that those are terrible in terms or fine control of heating devices. Pick up a Lutron 300W lamp dimmer at Lowes ($10) and it will allow for much better control as it's a slider and not a notched wheel.