Tank temperatures

Just yesterday I read a thread on another forum discussing coral colors with lower tank (75 degree range)temps being more vivid. It spoke of lower metabolic rates resulting in less nutrient and mineral use and higher o2 levels in the tank.
Basically growth was slower but colors were better.
This was more of a discussion so there really wasn't any evidence to back it up, it sounded plausible though.

With that being said I keep my tank at 79 degrees, but in the summer my wife loves to turn off the ac right before we leave the house, especially for vacations. I have come home to a tank with temps in the high 80s even low 90s at times and had no losses from it as of yet.

 

Here's my readings since July 2014 as to temperature. There are some outliers due to cycling period, cleaning the seneye device, etc. 79.2 is my average temp.

Oh and you can see my catastrophe event with the last red dip below the line. That was when the breaker blew during floor installation.