You could grab this, https://jet.com/product/Costway-4-Inch-Inline-Fan-Hydroponics-Exhaust-Fan-Duct-Cooling-Fan-Strong-CFM/b406965703bd4a2dbcc82e68ef578014 You get 15% off your first 3 orders too so that brings down the cost a bit. I stand by the carbon filter recommendation though.