I've got an empty Oceanic BioCube 29 gal nano tank. I've been thinking of setting up a cichlid tank instead of the usual marine system. Its been a while since I've done freshwater and want to know how to set up the BioCube for an african cichlid tank, or other type of cichlid species? Can I use the crushed sand from the previous salt water set up which I have cleaned out for starters? What do you suggest for filtration? The wet dry bio balls? Carbon? etc? Thanks.