I think most people will agree that carbon is a good idea.
Previously I had it in a bag laying in the sump (passive), since I got a phosoban 150 reactor and run Black Diamond, it really cleared up the water. I will get better use out of the carbon through the fluidized reactor, and more bang for the buck!
Carbon = yes
Phosoban reactor makes it cost effective over the long run.
Best
Doug