82 to 84, but only because i have no heater to turn down :nope:
stability is more importatnt, and 2 degrees is not a bad fluctuation from night to day.
IMO, anything 78- 84 in most cases, however what is more important is definitely stability coupled with the inhabitants. Some species had cooler needs and some warmer. The catalina goby is a good example, 68 is the only way you can even attempt to keep them for any amount of time.