exhaust fans and scrubbers?

so i have a 3 x 3 x 7 with a open 600w hps for flowering (week2)
i will be getting a 6in carbon filter for smell. i was wondering what i needed the cfm to be
to properly exchange the air. would i need my cfm to be double because of the carbon filter? i currently have a active air intake of 60cfm. i know i want negative pressure i just would like to know the range of my exhaust for my cfm with the carbon filter

After my issue with fan and scrubber I'd go with a size bigger than you think you'd need. I've got a tiny cab, thought 4in would be fine. Nope can't handle my ballast running 200w. Wish I'd got a 6, or even 8in and a fan speed controller