Ok,so I need a little help on what to do

So my grow room gets really hot,its a closet,dont know the dimensioins but its decent sized.Im about to cut a hole in the wall through the other side to have an exhaust with a fan in the hole,do u think this will help?and what should I use for smell,I heard Ona Gel works great,and DIY Carbon Filters,cant seem to find a cheap on though.any help would be appreciated!~!

Ona gel is one of the BEST odour killers around.
Don't know where you are but this is cheap.....
http://www.greenspirit-hydroponics.com/environment-control/carbon-filters/4inch-rhino-filter

thanks for that link,that is VERY cheap.Where would I find ONA Gel at?i havent been able to locate it ot websites really,everytime i try it comes up pretty weird shit.never has an order button either.well if u know where to find ONA id be appreciative,if not its cool the Filter u sent me the link for looks promising

take in cool air from outside,attic,another room..incomming from the bottom outgoing from the top(heat rises)..carbon scrubbers help..run an oscillating fan in the grow room(don't aim it on the plants aim it above them)...i dunno how many plants u have?..sometimes just air fresheners will do the trick..

well none yet,but i know the grow room gets hot from a previous grow,i had a 150 W HPS at that time and the room was reaching HIGH temps,and now i got a 400 WATT HPS,the room is big enough that u think it would be fine except the problem is theres a steam pipe in there that heats up the room 10 degrees,so i guess is hould do what u said and take in air from the other room and then blow out air from the top,thanks for the good advice

Ona available at same site... and just about everyother hydro shop going... tip Ona gel good .. the block version isn't so effective.... I use ona whilst drying and to p[alce aboyut as a secondary odour killer AFTER the carbon.
Can';t go wrong the a Rhino at the price in that link.. I've bought a few of the larger ones to save for later lol

Cover steam pipe in insulation and wrap in foil or some such heat barrier. Try using one of those hypothermia blankets