Ihave a 250 hps/mh and im thinkin on building a 3x3x6 cab. but i was wondering about heat and what kinda venting i should do. thinking about growin 4 to6 auto plants. is a carbon filter a must. if any one has suggetions please comment. thanks
Whatcha gonna do about the ballast? Those things get damn hot, and god forbid it burns out on you but the smell will permeate the small room and your plants. Oh yea, and not only does a carbon filter keep the smell out it filters out things varying from mold spores to dust.
don't grow autos. ruderalis genes, yuck. no point anyway - the only scenario where autoflower is a benefit is outdoors for short seasons or multiple crops per season. You'll want a carbon filter, too. Worth it.
I wouldnt get anything under 265 cfm for fans, you just need a intake fan and exhaust fan with ducting. Hook the carbon scrubber to the exhaust and the intake to fresh air and voila.