If you have an adjustable speed motor it is usually more efficient to set it at a slower speed to be able to scrub the odors better. Not sure how big your filter is but it maybe time to upgrade, especially if your grow volume is increasing. There is another way to extend the life and efficiency of your filter, and that is to cover the part of the filter (about 1/3) nearest to your fan. This causes intake to the filter to occur further back from the fan where the charcoal does not normally scrub as much as the charcoal nearest to the fan, and of course I'm talking about air being scrubbed first before going through the fan and then out of your tent And last but not least, it maybe that its just plain time to invest in either a cleaning solutions to wash your charcoal for reuse, or invest in a new filter.