Help with Ventilation...grow in progress!!

Well I got my 400 HPS in today and hooked it up. I have 5 little seedlings poking through the soil now but my temps are too high for my liking. My current grow space is pictured below. I currently have a 110 CFM in ceiling and a 4" ducting coming in from ceiling that is tapped into my AC ducting directly but its too hot still.

Right now I have to keep my door half open to keep temps to around 80, if I close em they shoot up to 85-86 and who knows how much higher as summer hits!!

So here is what I am going to do. I ordered a 290 CFM fan that is only .5 sones louder then my current one and I am going to cut intake holes in my wall between the closet and the room. (bottom, to the right of the door in first pic)

My grow space is 96 cubic feet, (6x2x. If I run a 290 CFM fan on the ceiling venting into attic, how large of intake do I need on bottom? I want to make sure I cut the holes big enough but not overkill because I am worried about smell getting out through them and also, I need to figure out a way to light proof em.

Lets here some ideas!!

hey web...

as long as you are pulling air out of the room and the fresh air that is replacing it is less than 80 degrees, you should be fine..

how does it feel in the closet?

I would recommend a more powerful inline fan than 110 CFM... and you better run that through a carbon filter.. it sounds like you wil be pumping the odor of cannabis throughout your entire home - not a good idea

I would go even bigger than 290...

I would go with at least 480 and if it were me, I would go with 700+... the intake is the least of your concerns. the air is gonna creep[ in through cracks and shit...

If you can, make the intake comig from the basement/crawl space.. that air is always cool..

WRAP your inline fan with egg crates.. they sell them in the bedding section at target... really cuts the sound way way way down...

iloveyou

Ok thanks for the advice!

I have a carbon scrubber in my attic attached to the exhaust fan. I already ordered the 290 CFM. I think that will be fine for my small space...I really do think its just the intake being limited thats causing the heat build up right now because when I crack the door the temps drop 5-6 degrees. I just want to be able to have my doors closed all the time and so thats why I am upping the fan and cutting holes in the wall. The wall is only drywall so it wil be easy enough to repair when I need too and easy to hide with a bookcase etc, when I need to as well!!