So I got a new used bio cube for a qt tank. Looking for ideas on what is essential for set up. I'm also thinking about letting my son make me a cool Lego city aqua scape! Anyone tried Legos in there tanks? I could use some sort of base I can hold down with magnets? Uh. Idk just throwing out random thoughts here! Who's done led upgrades to a 29 bio cube? Show me your cube give me ideas.