Thanks for the reply moneyshotpb. From what I've been reading, you are absolutely correct. Also it would seem that only 100 milliseconds, or 0.1 seconds of contact is required with the carbon for it do the job.

The fan/filter in this case was sold as a package. I assumed (big mistake perhaps) that the supplier did his homework in offering this package, in matching up the fan with the filter.

This morning I turned to the fan itself. I noted that the junction box was not fitted to the fan casing very well, with a significant gap on one side. I unplugged it and opened the junction box, then removed it from the fan casing. I removed a little material from the box with a file, but I couldn't remove enough to provide a good seal. So I reassembled it and foil taped the seam of the box to the fan. What was noteworthy here was that some the screws on the terminal strip were somewhat loose, which could have led to problems down the road. A loose connection means higher electrical resistance, which leads to heat, which increases the resistance, which increases the heat, etc. An electrical fire in the grow room is not a happy thought. So I'm glad I at least found and rectified that.

Alas, the problem continues. I can only conclude at this point that the filter they shipped me was pretty much spent, as far as the activated carbon goes. From a google search, the shelf life of activated carbon is two to three years. And while spent activated carbon can be reactivated, using steam and a chemical scrubber, this is an industrial process.

Going to beat on the supplier to replace the filter. If they won't do that, I will out them and shop elsewhere. A can 66 looks pretty good at this point, but will research further.

One last question - am I naive to think that the filter will remove ALL of the odor?

Thanks for any help you can offer.