What heater do you use and how stable is it?

[Saltyreef]

Ranco temp controller with a hygger titanium heating element. Steady at 76-77 with 77 degree setpoint. No tenths of a degree readout so it could literally be .1degree from the setpoint.

I have 3 undersized heaters and 3 rancos so theyre setup to not overheat the tank and if one fails i have two more redundants.
I may change this to 2 and hook up the 3rd controllee as a overtemp failsafe.
I figure undersized heaters always have worked for me so i went that route.

 

[DivingTheWorld]

Any controller or just the built in temp controller?

Just the Apex probes. I run two probes, one at the entrance to my sump and one at the exit.