From the Ron Shimek article...
"The average temperature calculated for all 1000 + coral reefs was 81.7°F
. Over all reefs, the average lowest temperature observed was 76.4°F, and the average highest temperature was 86.4°F. One way that these data could be interpreted would be to say that for most corals and coral reef animals, the best conditions would be between 76°F and 86°F, with the average being about 82°F
I have my temp controller set to kick on the heaters if the water drops below 80 and the fans kick on if the temp goes over 82. When I was running metal halides my temp would vary between 80 (lights off) and 82 (lights on). Now that I'm running LED
's my temp is pretty solid at 80.