I have a Fluval 305 in my 55g. I also run an Emperor 400 and 280 HOB's for added filtration. If you have a decent amount of African Cichlids then chances are yes you need more filtration. You will read on here often that you can't have too much filtration. As far as the media goes the carbon is best used for removing medications used in the tank. Other than that its pretty useless and expensive. In my Fluval I run the biomax noodles and filter floss to polish the water. (Pillow stuffing that you can buy at walmart etc very cheap.) You could always add more biomax or some people use pot scrubbies to help with biological filtration. If your currently cycling a new tank it is normal to have raised ammonia readings. An ammonia remover media may slow the cycling process. If your tank is already cycled then it is possible that you do not have enough filtration and good bacteria to take care of the existing ammonia. So IMO I would get another filter. Either a canister or HOB. I am a big fan of the Emperor 400. Its easy to clean and does a nice job filtering.