Carbon has a functional life span in your tank of about 3 days. Carbon will help reduce odors, absorb medications and many many other chemicals that might get into your tank (like the flea spray you just put on a cat/dog for example). Carbon will not clear up a cloudy tank. And carbon is not needed in your tanks for daily use. Carbon has a purpose, and adding it to your tank when its needed is very important, but its not needed daily. infact in order to have useful carbon in your tank daily, you would have to change it twice a week.
I have no carbon in ANY of my tanks, but there is can of it in the basement ready to be deployed at any time if its needed.
