I am running a 90 gallon tank with just 1 t-5 strip atm, to enjoy the fish. Next week I'm looking to up the light to 2x 250 M/H 14k. Is anyone out there running this? If so are you doing it without a chiller. I really don't want to put that kind of money into a chiller. I was hoping that 3 or 4 inch fans in my canopy will do. Thanks

I think you'll be fine with some fans. I highly reccomend the 4" fans from Radio Shck that run on AC, so you don'tneed an adapter like you do with the DC computer fans. They move a TON of air, and are really quiet. They're also $25 a piece, but totaly worth it.

I assume these are going in a canopy? If so, remember to have the fans push cold air INTO the canopy instead of pulling the warm salty air out. It's hard on the fans, and will wear them out quickly. You might also look into one of those cheap 7" clip on fans they sell at places like Wal-Mart. I have one of those blowing on my sump, in addition to several of the Radio Shack fans in my canopy. I have 2x400 over a 120 and it keeps my chiller off most of the time.

I'm thinking of using 2-4 inch smart fans, self regulating based on temp from 68 to 112 CFM. These will be installed in the canopy. I was going to have one push and one pull, but now that you mention it both pushing may be the smarter way to go.

If you have one push and one pull, you're only moving the equivilent ofe one fan's worth of air. One fan pushes 100 CFM in, one pulls 100 CFM out. If they're both pointing in, you're moving twice the air :)