Quote Originally Posted by bugmenot11
Please excuse any confusion, English is not my first language.

Can anyone guess how many cfm this is? (video below)

It's a 120mm, 115 volt fan I bought but it says nothing about cfm and I need to know in order to find out what kind of carbon filter to make.

The hole of my grow box, as well as the fan, is 4" across.

I have no idea how long I should make the carbon filter in order for the airflow to be enough for the smell to stay with the carbon long enough to eliminate the smell.

The box is 2.6 feet in height, 1.7 feet by 1.7 feet length and width.

Video
YouTube - IMG 0417

Also, I plan on running at least 3 - 65w cfl's (4,000 lumens each) just in case you want to take heat into account.

Thanks
Could not tell from the video