The article does make some good points. My only problem with it is lack of sources. It's okay if he is just presenting this as opinion, but a few sources at the end wouldn't hurt. Back to the point, carbon isn't all bad, and I do keep carbon filter cartridges for my tanks hanging around. Mostly in the event that I need to use medications. My problem with carbon is that it give new aquarists the illusion that all they need to do to "clean" a tank is to change the filter cartridge. Yes carbon can make the water look clear, but it doesn't provide clean water like regular water changes will.