I stuck my hand in my tank yesterday noticed it was cold ( 71 ), I have a Profilux 3 which sends me an email if temp drops 2 degrees but I had turned off the alarm for some reason and never turned it back on duh? Anyway lucky escape for me all is well now. So I was doing some research and found an article
http://www.ronshimek.com/salinity_temperature.html stating the temp should be higher around 82 -84 for corals as they thrive better at higher temp. I keep my tank at 78.8 how about you ? my corals do alright but I wouldn't say they thrive