Replacing the Charcoal in your FIlter???

Hi all, just bought a Can 33 for my grow room, and I was wondering, I see there are screws on the side of the top cap of the filter, so I was wondering, instead of just throwing it away (I can't believe no one recycles these) can I refill it with new charcoal?

Sure you can, with cheap charcoal granuales from the Aquarium shop.