I thought about it and looked on here and found somebody that did it. The problem was the carbon likes to float up, so he put a spnnge in there to hold it down.So you'd remove the bio-balls and put your carbon in there?
Also think the CPR would be noisier? Still haven't heard any bad press on the Remora, probably where I'm goin. Can use the canister for chem filtration.Remora Pro would be the best choice IMO..