Odour control is the difference between a grow room and a problem. Get it right and nobody knows the room exists; get it wrong and no amount of anything else matters.
The three approaches, in the order you should try them
Filtration. A carbon filter on the extraction removes the smell before it leaves the room. This is the proper fix and everything else is a supplement to it. See carbon filters.
Neutralisers. ONA gels, blocks and liquids bind to odour molecules chemically rather than covering them. Used outside the room – in the hallway, near the extraction outlet – never inside, where they taint the crop.
Ozone. Breaks odour molecules apart at the outlet. Effective, but ozone is harmful to breathe and to plants, so it belongs inline or in an unoccupied space, never in the tent. See ozone generators.
Why filters fail
Almost always one of four things, and rarely the filter itself:
Wrong size. The filter must handle your fan's airflow. Undersized means air passes through too fast to be scrubbed.
Positive pressure. If the tent is pushing air out through gaps rather than pulling it in, unfiltered air escapes. Extraction should slightly exceed intake so the tent sucks in a little.
Exhausted carbon. Filters have a working life – typically 12 to 24 months of continuous use. They fail gradually, so you get used to it before you notice.
Get the negative pressure right
A correctly set-up tent visibly pulls in slightly at the sides. That means every bit of air leaving is going through the filter. If your tent is bulging, your extraction is undersized or your intake is too open – see extraction fans and ducting.
Why buy odour control from The Hydro Bros?
We are a hydroponics shop in Croydon and discretion is most of what customers come to us for. Tell us the room and the fan and we will size the filter properly. Discreet UK and European delivery, and excellent customer reviews on Trustpilot.
