Running a positive pressure system in my house since many years, I agree that sucking in fresh air from outside and filter it with a HEPA filter makes more sense.
You probably need to make sure you use a fan that creates enough pressure to get the air through the trickle vent as well as a filter. A duct fan might be more suitable than a PC fan for this.
You probably need to make sure you use a fan that creates enough pressure to get the air through the trickle vent as well as a filter. A duct fan might be more suitable than a PC fan for this.