Only reason for 4" is becuase the closet is only 70 cubit feet ... even with the carbon filter, hood, duct muffler and damper I still can change the entire volume of the room in 1 minute. Plus I dont have to deal with cutting big holes incase I need to patch it up later down the road.

the idea of taking the intake from the basement didnt come to me till I actually went to post my ventilation problem but after thinking it over I think its the best way to go.

I'll just slap on a filter sock and a damper and pull it right through the floor. I'm going to have to take a hole saw to the hard wood floor though

I think I'm going to buy some co2 test kits to check the levels in the basement ... co2 sinks so there should be plenty and if the basement gets to cold in the winter I can just unhook the duct from the hood to gain some heat from my 400w HPS

I'm just gunna have to stop having people fish bowl the basement with weed and stoges becuase im pretty sure smokey air aint gunna halp my plants. Maybe slapping on a HEPA filter would help but there 85.00