Carbon filter help! What size do i need

I am thinking of using a The AgroMax 47”x47”x79” Grow tent and I was wondering. How big of a carbon filter do I need to use? and should i use 4" ducting or 6" Thankyou!

6". Go big, grow big. Same size filter obviously but make sure your fan/blower can move the needed CFM to flow and not back up. Ducting as straight a line as possible both intake and exhaust.