That sucks, with a fluctuation like that, you need the heaters. I have Bichirs, and have had Loaches and Angels, all in the upper 70's and they did, and do fine. Don't worry about it, it won't be a problem.
FireMedic;1784781; said:In the 380 gallons of actual water in my system, I keep the temp at 78deg with little to no fluctuation. During a 25% water change I might see 2 deg change.
I run three, 400w heaters in the sump.
Large volume = stability.