No need to, somepeople do some dont'. Anything that comes in contact with the water will have the bacteria adhere to it. The trick is to use your filter media until it is literally falling apart and not to replace it all at once when you do have to replace some.
personally I run carbon in all my tanks except for my 125g reef. i havent antied up for a carbon reactor yet and don't feel throwing a bag in the sump will do a good enough job.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.