I suppose I am being a little impatient with how fast these guys grow but I'm just so excited to have them. The assistance on keeping algae under control was one of the reasons that I wanted to get involved with moss balls. I've got a 72 gal bowfront tank that's moderately planted, is 1 ball enough for algae control or should I add more... pardon the pun but do they do better in "pairs"? :P