I saw post number 7. I'm just trying to figure out what I need to do. I really don't want to have to build a frame like you did and then figure out another filter situation...
I was really trying to figure out something that would be an easy solution. I mean if I can feel air going through my intake ducting does that mean the HEPA filter was restricting the airflow? With the hepa filter off, and the exhaust fan at speed 7 I still have my tent sucking in pretty decently..
Just trying to figure out what I need to do to fix it without having to build a structure like you posted in picture number 7