Passive intake vs fan intake and filter

Is it worth spending the money on an intake fan and HEPA filter to make sure that I don't get powdery mildew in my tent. I have been using a passive air intake but I ended up with powdery mildew. Not saying I got powdery mildew because of no filter on my passive intake. But I'm sure it would help right?

If your worried about PM you will need a clean room to sterilise yourself so your don't carry any spores in with you.