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Ona gel is Highly recomended here as an odor controlle if a carbon filter is out of your budget. I also use knock off odor gels and have had success keeping the smell at bay.
To an extent yes. Its basically a 'super' odor absorbing gel. The knock offs I use do a great job, but for only a few weeks. Ona has been recommended for up to 90 days. Ive never used it myself, but many growers here say it is great.
It will never be a crabon filter that scrubs the odor away. It masks and absorbs, but at $10 vs $80. Id say its worth it.
When I've used it I liked to place it in between the plants and anywhere where someone would be able to detect the sweet sweet smell of the plants. Say you have stinky sweet in your bedroom closet I'd place the ona in the bedroom and close the door that way it it works as an additional barrier.