The reason I asked because I read that he had a set up(don't know what kind).And didn't like the clarity,so he got a used wet/dry.Then he said" Seems his is preferred if you have fish and corals".which I looked at it as "him" was the guy who he got the wet/dry from.So I wanted to know what his tank was.If it was a FO then use it as a wet/dry(as filter)If it was anything else then I'd say take the balls out and use it as a sump!Sorry,I wasn't sure from what he wrote!You can never assume what someone is thinking if it's not typed out unless you saw his setup and know more then what is typed!