since the filters job is to remove the smell, its probably the filter. it may not be matched well to your fan or it could possibly just not be a good filter. make sure its a decent filter by seeing how thick the carbon is. if its on a 6"duct, the filter should be at least 10" wide. the carbon needs to be 2" thick. so 2" carbon + 6" inside + 2" carbon = 10". ive had a 1.5" filter that let smell pass and replaced with one thats 2" thick and fixed the green smell. i dont always trust what the growshop says is best to buy, sometimes its what they need to sell, lol. buy a namebrand filter! phresh, phat, etc. next make sure you filter is rated for your inline fan. all filters have an optimum working range. and dont forget to take into consideration the duct between the 2. ive read that 1 90deg bend can cut a 400cfm fan down to 200cfm or some shit like that. this is where an anemometer can come in handy. this meter can tell you exactly how much air is being pulled at the filter. then if you know what the filter is rated at youll know what you need. if you cant find out, for $200, scrap both and replace! its not worth the trouble the smell could bring. next thing to think about is the strain. some strains are just stankass! if you know the brands of the filter and fan, find their website specs and see how they match up.
, and yes where the air exits from the duct. Just an idea
