Please help with exhaust into attict

Hey guys,
I have just finished designing and creating my grow room in a 2x4x8 closet. I have a 400 Watt MH/HPS with a cooltube reflector, on the exhaust of that reflector, i have a 540 CFM inline fan attached to aluminum duct, that duct goes from the fan into my ceiling. I cut a random 6" hole in the ceiling of the closet and then moved over the insulation behind it, i then pushed the aluminum duct in past the insulation, then sealed it. Could this potentially cause any problems i should know about? can this cause a possible mold problem?
Thanks,
Crusherdub

anybody? i kind of want to know if im creating any problems as we speak, haha

Should be fine. You might want to istall a damper, most roofs are vented so heat and moisture can escape this may allow hot attic air to flow down your ducting back into your room. Not a problem if your fan is always running. I've done a lot of remodels where people have run there bath fans right into the attic.