I have a 14g and 29g BioCube. I have removed the Bioballs in favor of natural filtration. From what I've gathered, bioballs, as time goes on tend to build a lot of nitrates. You are supposed to remove and clean them from time to time. I think detritus material can gather in them as well. There are many debates over this topic out there. In my opinion, LR rubble is the way to go along with macro algae. I'm sure others will chime in who have more experience than I.