As Shane said, its more about consistency. This is especially tricky for the smaller biocubes and such, because their temp can swing a lot more.
I would suggest buying a small fan to blow accross the top to blow any stagnant hot air created from the lights away. That along with a heater to make sure the temp doesnt drop much and you should be able to keep a pretty steady temp :)
82* is a lil high, it can be fine at that temp but your pushing it. If anything were to cause it to spike higher it wouldnt take much to start harming stuff. A better temp would be 78-80* :)