CS does not differentiate between good or bad or medias. Try putting CS in an aquarium which is biologically balanced with good and bad bugs. It kills them all. This will eventually get the fish because the biological balance has been killed. All successful aquariums are run using bioligical balance. That is why if you buy a brand new aquarium set it up and overload it with fish they will all die.
Sorry, but the "good" bugs don`t kill the "bad" bugs in an aquarium. The biological filter works by the bacteria (neither good nor bad) converting nitrates from fish poo and uneated food into less harmful nitrites. The cure for it is less fish and more partial water changes. Nitrogen build-up is the real name for "new tank syndrome". Marshalee, former aquarist...
