Great DIY, think I'm goona give it a go myself, save a bit of cash and also a bit of DIY satisfaction!

How effective have you found this filter and for what dort of set up are you using it for. Mine would be for a 1.4msq tent with a 600w light?!

I'd say over 90% of all scent gone. I smell it a tiny bit because I know whats going on but after buddies visit my place and go home, I asked them if they smelled anything odd in the place (without mentioning the plants) and only one mentioned he smelled a bit of a musty odor.
Not sure what that means because I am growing in DWC but it could of just been the place is a little musty from being closed up so much.
With the box set-up of the filter, you could also set a jar of popouri (sp) or ona or something like that to scent the air coming out as well

That's a pretty cool DIY filter design. That gives me some ideas. Thanks

Just refilled for the 2nd time on this...so each fill seems to last about 1.5yrs

in case anyone wanted to know about length of time. Although how much you are filtering will dictate if you need to refill more or less often.