Personally, I agree about there being a balance, I prefer having a equal to small (read 10 cfm) positive pressure in my tent so I dont get the smell coming out, but I dont worry about a carbon filter where I'm at right now so it's always about an even pressure differential. But yeah I try to have about an equal amount in and out so I dont deprive the plants of any air they need. The idea of having a positive pressure differential is mostly so they constantly have fresh air and arent deprived of air (as you pointed out). But yeah, for me a slight positive pressure differential to me is good as it pushes out any possible mould spores so they dont suck in more and push out not get sucked in, but most give a slight positive pressure differential because, depending on the outtake fan, the little extra pressure in will also make it a bit easier on your outtake fan and push a bit more on.No your
No I did think cfm was carbon filter something sorry I should of thought about it , and I dont actually no but if more air is going in than out surely the smell will start seeping through door cracks if no negative pressure ?
The positive differential is so small though that the smell shouldnt be any issue as long as it's a good tent that's sealed well. The biggest time I smell my plants is when I open the tent... and then BAM it hits you. The positive pressure differential some growers use is very slight (again a few cfm like 5-10) so mostly negligible.
It's kinda a game of hot potato with the smell. Which is funny because you can grow shrooms, peyote, salvia and heck you can even grow freaking opium poppies without filters so it's frustrating needing a carbon filter for an herb
Sorry that was more of a rant than an answer. Anyway, let me know how I can help.