I would get rid of the carbon. As stated above, after a while it becomes ineffective and can actually start to leach the things that it has absorbed back into the water. Carbon isn't really necessary except to remove medications from the tank after treatment. Save yourself some money too!
I don't have AC's filters, but I have Aqua-Techs, which are similar. I do the same schedule as supradupafast, rinse out the media and filter in the old tank water, squeeze out the sponges, clean out the intake tubes and impeller(and hang on to the bio-media) about every two weeks.