I started to get the odor outside of my growroom in less than 3 weeks from germination. Carbon scrubbers are very effective if you can manage to vent it properly and replace what's lost with intake air. If not look into ozone generators or other carbon filters such as the febreeze "true air" or Holmes carbon air cleaner. I don't know where you are from but you can find these at Walmart, Home Depot, Lowes, Sears, ect...