So I have been going through my first cycle on the new tank this last week and one night I decide to turn the tank lights(150watt MH closed canopy) on for a little while. I haven't been running them to cut down on excess algae. The tank has been stead at 78.9 - 79 degrees all week, but after about 3 hours with the lights on the temp was up to 81.6 degrees (ambient household temp was 74 degrees). Is there such a thing as an acceptable temperature swing or am I going to need a chiller? I was really surprised that the temp changed as much as it did, the canopy even has 4 built in cooling fans.
Thoughts?
TIA
Moo