Originally Posted by 27mtaylor
You can have a fish only tank with CC. The nitrates will be higher in a tank with CC and lower in a tank with sand. I have CC in my tank now and my trates stay around 15 ppm. This is fine for fish only, but if you decide to do a reef, you would want those trates down around 0.
It all depends on how fine of CC you have in the tank. Normal CC collects debre, x-fine CC does not, and is very close to the fineness of LS.