Nothing wrong with using carbon, but it will pull out any liquid form of additives. If used, which I have for years, only use for short periods of time to clear water. Most research says that carbon clogs after no more than 10 days. I have used it for 2-3 days, then remove. A little will go a long way. While using it just do water changes, if needed, no additives.
I have used chemi pure also and like the way it also makes the water crystal clear with longer runs of it.