This is sometimes a confusing issue. Generally we buy two types of fans: blowers - like the squirrel cage type push better than they pull. In line fans pull better than they push. So, if it's an inline fan the filter should be first. If a blower, the filter should be last. I hope this helps to clearify the differences between to two.
grey1223 Reviewed by grey1223 on . Questions on some products I'm trying to plan my grow room redesign coming soon after this flowering phase finishes and I was wondering if anyone has insight on the following products: Odor Sok: these are filters that are much lighter than conventional carbon scrubbers. They are made with fabric made out of virgin activated carbon as opposed to being filled with the carbon pellets. I was curious how well do these flow and how well do they filter out the odor? SolarMax 400watt MH conversion bulb: These are normal Rating: 5