Originally Posted by TheChad
Wow its amazing no matter how much you read, you can't ever find a single answer.
Keep in mind that our tanks frequently have a variety of critters and corals from around the world's oceans.
One species might come from a tropical reef setting where the normal temp that it thrives at is 84°.
Another species might originate from a completely different part of the world where it's ideal temp is 72°.
Even critters that come from the same exact reef might live at different depths, and as any diver has found out, the water temp near the surface is warmer than the water temp just a few fathoms down.
The real trick for us aquarists is finding the happy medium between what the different species in our tank can comfortably tolerate.
My tanks run in the range of 78°-83° between the air conditioning and cooling fans, and so far everything seems pretty happy at that range.
Obviously I don't keep any "cold water" species.
If I did, living here in South Florida, I'd have to invest in a chiller.
The a/c and the fans just wouldn't cut it.