Yes and no.  Carbon is good for removing alot of contaminants that cause odors and discolored water in your fish tank.  However, they also will remove most of the fertilizers you use in your tank (as well as medication and many other additives.)  Many plant tank owners will either user carbon for a few days every couple weeks to "clean things up a little" prior to a fertilizing process.  Some do not use carbon at all and just increase water changes.  Others may use carbon and just leave it in for longer periods so that it "clogs" its ability to remove the fertilizer.  Then they change it every few months and start the cycle over again.