I was afraid to ask, but...

[Troy-N-Eli]

Has anyone ever heard of "bio-balls"?  Saw some on ebay, have no idea, never heard of them before.  I feel dumb for asking, since there's probably been talk about them here before, but I haven't found anything about them.

Not sure I want any anyhow...little leary of putting any "balls" in the tank.  Thanks folks.

 

[Avalon]

Yep. I got a couple myself  ;D

Seriously, they are a filter media for any filter that will hold them. They are extremely popular in trickle filters, and are one of the best medias for cannister filters. The purpose is to increase surface area for bacteria to grow on. The more bacteria you have, the better the chances of complete nitrification all in one pass of the filter.

Oh yeah, you don't just drop them in your tank if that's what you were thinking (*snicker*)