Why is my filter leaking smell

Another option is adding another filter.
They make inline filters.

So you'd have Filter>Fan>duct>InlineFilter>ExitVent

I think Can make them.
Obviously , like any fliter, it reduces airflow so you'd need the leg room on your fan to account for that.

itsaliveterps said:

I don't have a choice 5% of smell is leaking outside from the vent I can't get a new carbon filter until another 2 weeks I can't afford to lose my project especially now but of course I don't want my bud to smell like ona gel... :/

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If you can't afford to buy another carbon filter at the moment then just keep your windows closed in your house. That will help prevent the smell from leaking out. And put your ona gel in the room next to your grow

Fish scale said:

If you can't afford to buy another carbon filter at the moment then just keep your windows closed in your house. That will help prevent the smell from leaking out. And put your ona gel in the room next to your grow

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Its a wall vent that goes outside