@DougDawson This is something I have always wondered. I have run anywhere from insane (box fan taped to the side of a panda film tent, facing in with a 6 in exhaust fan, always on. Like a hurricane.)
to just passive (sitting in an openish room, little clip on fans or pc fans, but no real forced exchange) and both worked. The hurricane tent was definitely harder on the plants. Maybe a happy medium between none and all is the ideal haha.
Having said that, this is timely topic for me. I’m getting a new tent Saturday and have been thinking about this very thing. I’m imaging some emt conduit and zip ties, or paracord. I’ll post my hack solution here for all to see haha.