U must keep your AC on 55 degrees LOL we had three 400s with fans on a 110 with a 75 gal sump and the tank was a constant 85 degrees. Im a firm believer in over kill is better. then again im an SPS ADDICT so when NY had its black out a few yrs back i lost 14K in acros If i do another tank im gonna wait a few yrs and do a 400 with a 150 sump all sps and just sit infront of it and sip a beer smiling. I just want to finish the remodeling (3rd time haha) here 1st