How hot is your tank?

I run mine around 79-80, although a bad thermometer had my tank at 86 for a long time before I noticed, only thing that had a problem with it was a favia that receded.
 
If the corals weren't acclimated to the temperature or it changed quickly, absolutely.

I keep my tank "cold" at around 74-76. I've heard so many horror stories about exploding and malfunctioning heaters that I pulled them out of ALL my tanks. I have to keep the house warm for my parrots, so, all in all it works out very well, and it's one less piece of equipment I have to worry about!
 
80-82 because of the warming trend here. Durring the dead of summer though it'll kreep up to 83 pretty quickly though. Otherwise durring winter and spring I keep it between 79-81.

-Justin
 
Mine got up to 85.1 the other day. This morning it's 74.8. No problem. I've already unplugged the heater for the summer.
 
75-84 over the course of the year. it got up to 88 once, and i lost a fresh cut frag. (last summer). other than that, all the high temps did was cause my corals to close for a bit. however, it soon went back down to 84ish, and everything opened back up.

yesterday my tank was around 79.
 
summer time 78-81 at the highest.. right now since it cooled down the last couple of days the tank hasn't gone over 79.8
 
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