I have found ONA to be more of a smell coverer than a smell remover.
The "cover" speaks volumes to anyone smart enough.
I made a DIY filter that worked like a charm through my first grow.
When I added a T-8 lit Mothers Area, I started to get smell issues,
as my next Crop was chosen for skunkiness. So, I added a Whisperline
fan and a Can Filter on its intake in the mothers area, with a duct taking
the output into the tent, where the air is filtered again before leaving the
house.
So far, so good. :0)
I did have to deal with a positive pressure in the tent issue. This lead to
smell being pushed out of the tent.
Good luck!
JD