Report 6.jpg in Grow Rooms 1 Posted March 6, 2011 I removed that outer "white" filter on the charcoal can. That will just make your fan work harder, and is unnecessary. My fan started making louder "whirring" sounds and I removed it and my filter lasted another 6 months without clogging..(esp. dust) Remember that outside filter is good for about 6 to 8 months, the charcoal is millions of years old, and only needs to either be cleaned or replaced. I replaced my filter after 14 months. Looks good though!!