Ok so on my 25 gallon tank at work, I upgraded my lights to a 250 hqi....it runs for about 9 hours. The tank temp in the morning before the tank lights turn on is 74, when they turn off its 82. Its been like this for 3 weeks and nothing really bad has happened yet. Although my angel and clowns started beating up on my cardinal for no reason at all.....but the corals and inverts seem ok. Actually they seem bigger. I have 3 or 4 RBTAs, some leathers, GSP, and rics, some purple mushroms and anthellia. I have a fan on order, but just wanted to see what you guys thought. To much heat to fast?