Mine is 79 to 80.5 as day goes on with lights on, these temps dont show any negative effects on the corals whether acros or other types of sps or the lps. And I have a wide variety of all. Pic attached for reference.
I set up a tank at my friends house and he leaves the windows open during the summer with no fans on his tank and runs two 250w halides in a canopy! His tank I didn’t measure but it was HOT to the touch. Not warm, hot. If I had to guess it was maybe 90 degrees on average and maybe got cooler during the night. The acro frags I out in there survived and grew slowly, more so because of his husbandry was bad but I was shocked when I felt the temp when I was there last. The acros were colored really wierd, tan with fluorescent colors in there kinda swirled in spots. I put them in my tank when we took the tank down and they darkened up to normal colors quick and started growing right away.
A tank can be run MANY ways, as long as it’s consistent. I used to keep my temp at 75 in my last acro tank.