Carbon filter not working

Hello. My carbon filter doesn't seem to b working, i have it b4 the fan so air goes from filter into the fan an out do carbon filters only work one way?

where does it smell
in the room or at exhaust point

Carbon filter works best when you suck the air trough it but still do the job when you push it trough.

Maybe the filter/fan is not big enough for your room?

how do you work out what size you need? i have a 0.72 cubic meter room

Thats the size of my grow tent too. The smell is coming from the exhaust tube. The air gets sucked through the carbon filter and then through the fan. Really doesn't smell like its doing anything and this is only 3 weeks into flowering. Waste of 35 quid. The guy in hydroponics store said it should be outside the grow tent and the air should be pushed into it so gonna go buy more ducting and set that up to see if it helps. Raging....

ok one more point have been doing a little bit of reading up. The carbon filter is attached directly to the fan which is really strong. Could the air be getting sucked through it too quickly, cud that be my problem?

Nothing is going to cover the smell completely...

Make sure its is sized right for the room and for the fan. Shouldn't matter too much if it is pulling/pushing air through, I've done it both ways.

make sure theres activated charcoal inside the filter....no charcoal no smell getting filtered....also you want to pull the air through the filter... then vent it

Your air is going through it to fast. The filter should have a CFM rating on it. I have a carbon with over 100 plants and no smell at all.

The best thing you can do for the smell is turn around the air mass of the room every minute.

If your grow room is 8x8x8 = 512ft3 than a 500cfm fan with appropriate filter will work best.
1 turn ever 2 min isnt bad as well.