Odor control is a tough problem. I have tried counter-scents (bloody obvious by themselves), activated charcoal (OK, but very expensive, bulky and require periodic replacement) and ultraviolet (UV) ionisers.
The UV units, usually a UV fluoro tube and a blower fan in a tubular housing, work a treat and are cheapest in the long run despite a high initial purchase cost. Those with good familiarity with wiring a fluoro ballast might build their own out of parts and save a packet.
UV ionisers also have the upside of killing pathogens while they knock down scent. In fact, they're so good at killing scent that you should limit the amount of time you run them in a flowering area. I run mine 5 mins on twice an hour. Ionisers can reduce the scent of your end product if you don't run them on a timer!