As of last week until now with the cooling fans upgrade, my range is 79.6-80.1 The heater kicks in, which is very rare, at 79.6 and the fans kick in at 80.1.
Before this, I had a single icecap fan which is old...really old. One of the first equipments I bought since starting this hobby. The fan was great, it will keep the temp in control in the winter/spring/fall but it has a problem with starting up. Sometime it would not start and I would have to manual spin the fins to give it a boost. So this reason, the tank was up to 83 sometime.
So with winter approaching its end, I decided to do something about the fan. I replaced the old Icecap with a Tunze aquawind and what a POS the aquawind is. The biggest money waster I've ever put in this hobby. At 75bucks for the fan, it does jack-crap. My tank was actually heating up compare to the old Icecap fan I have. With the aquawind, I was running at 81.5. This is unacceptable to me since this is in the winter time. So I went to a local computer store last weekend and bought two 120mm fans(rated at 110cfm each) and wired it up and it worked perfectly. Temp never exceed 80.1. In the summer time, it would be another story. But I usually run AC and the fans will keep it in control.
I don't think the gig cares too much about temperature. With the Icecap not turning on on some days, the tank was up to 83, and the gig didn't seem to have a negative reaction to it. And from what I understand, in the wild, these things get baked under the sun during low tide, so the temperature tolerance must be pretty good.
Nick, what temp do you have the tank running at?