Marijuana grow room

Frow a fellow grower:

Hello i am a first timer and am all set to start my grow but i was testing system out and my grow box (36L x 48W x 6.5H) is too hot. Background…

Have a 6" mh/mps 600W hid cool tube light, is great can put hand within 4-5" without being to hot for hand. I have a 354cfm inline exchange fan with duct blowing into tube of light and exhuasting out of box to outside through window. I have a 50cfm bathroom exhuast fan in top coner of box to expel used air. I have two 3" holes screened with one 4.5 hole that has a computer fan (think is like 42cfm?) on each bottom side panel for air intake. I also have one oscilatting fan mid way up in back corner for air ciculation, but think gonna need to add another on opposite back corner. I do have 2 other computer fans and a 4" inline fan not in grow box or in use at this time just extra parts rt now.

With light on and box closed for good hr to 2 temp reached like 86 in middle of box and 81 at base of where plants will be.Also humidity is only like 25 rt now without water or plants in box im assuming will have no prob reaching the 50-60 once plants growing and water in resevior. If humidity gets to high will just put dehumitifyer in. My prob is the box heat, Im told that if box gets to a high of 80 will still be ok but idk as i have never grown before. I was wondering what advise if any you can offer…

I dont know if should put other osc fan in with both spare computer fans for mor air flow then was thinking could put 4" inline fan in middle of back panel at bottom as air intake or maybe put

Inline fan in top corner opposite exhaust fan as anothet exhaust fan as to pull more warm air out… I dont know plz help, thanks

Oh yes box is lined with mylar too so idk if that has affect on temp too.