passive or forced intake?

i have a 4'9x4'9x6'7 grow tent
600watt light system
ventilation will be carbon filter>ducting>hood>ducting out of tent>400cfm inline fan>ducting to attic.
i cannot have any odor issues.
was thinkin to have a fan thats like 172 cfm for intake
would passive or forced intake be better?

Generally small grow rooms do not need forced intake, passive is more than enough although with passive intake the vent size for the actual intake is quite important, too big and well you dont get air blowing in very much, too small and not enough can be pulled through for the size fan you got. There is a way to work it out although i dont know personally, my tent is cool with just passive and i run at about 400cfm on my 6inch ruck high powered by reducing on a fan speed controller (stepped voltage one).

I dont think the benifits of forced intake are much in a small grow with the right size vents and a decent extraction. Depending on ambient temps i would say that cfm rated fan should just about manage for a 600watt Hps but probably not too close to the plants.

Best way to work it out is run the tent with fan and light and see what temps would be at the tops of the plants then a stronger extraction might just be all you need.

Forced intake with cool air from outside or another source would inevitably help with keeping temps lower. Peace

appreciate it man. im gonna go ahead and to do test runs and see what happens with the temps

You might find the carbon filter and bends in the tubes reduce air flow, aim to have a straight 18inches either side of the fan with no bends if possible. Theres lots you can do to increase and decrease fan strength, even take the carbon filter off completly and have no tubes just the fan at the vent port of the tent exhausting out.

Cooltubes and air cooled reflectors make a big difference too and your fan is ideal size for one of these. Good luck

well i have to use the carbon filter cuz of the odor. and i should only have 1 bend in my ducting where the carbon filter attaches to the hood by ducting. the rest should be straight. besides when it goes vertical to get tp the attic. and i guess it would also be vertical when the light is low to the ground at the start of the grow cuz my port hole is up top and so is the attic lol

Run the tent and check temps, too high then cooltube or bigger fan or forced intake of cooler air. peace

will do. thanks