wow 500 big ones every 18 months thats pricy but not quite sure how this works can you add a link please ill gooogle thisI would have to suggest a large carbon filter with squirl cage usually comes pre built from the grow shop im going to buy the most expensive and largest one for my two producers. 500 bux
Its shelf life is about 18months. Which would be about 30 buxs a month. and after that about 2-3 hundred to replace carbon filter. It act as both a dehumidifier and a scent remover. My friend has exact same model and we can literally smoke joints right beside it with out any smell what so ever leaving the room, there also will be no smell within minutes.
The ones that come with producer are good but are to expensive to replace and do nothing to reduce smell when trimming or opening the doors.
can you point out the model your friend has and how he uses it thanks