Carbon are those tiny black granules that are packed into the filters they sell you at the LFS. They help absorb chemicals, but mostly they're just a money making scheme by the filter makers because they have to be replaced monthly and you've gotta keep buying them. The reason I ask is because (contrary to some people's beliefs) carbon does absorb ammonia. It can give you false readings that the ammonia is dropping if you let it run through the filter enough.
Whatever you do, don't throw away the cartridges in your filter. That's the main place the bacteria is trying to grow. If you shake one and hear little things moving inside it, take out some scissors, cut a slit down the side and just shake out the carbon and put the filter back in.
That being said, there's a reason you haven't seen even a hint of nitrItes yet and we'll figure it out. If you're dropping that much ammonia, you should ABSOLUTELY have some level of nitrItes in the tank. NitrItes are the byproduct of the bacteria eating the ammonia. To put it kind of grossly... The bacteria eats the ammonia and poo's out the nitrItes. There's no way it's eating that much ammonia and not creating nitrItes. You said you are using a dechlorinator?
