Advice about sumps

[Richer]

Originally Posted by molybdenumman

I have been told that they significantly increase nitrate levels in your tank. Has anyone observed this?

DanTheMan

I've read that also... in fact, its probably one of the most consistant things that I've read about in this hobby. Bioballs trap debri, which eventually breakdown and produce nitrates. Bioballs could work if you are constantly cleaning them, but who wants to do that?
There's nothing wrong with them if you're just doing a FO, or FOWLR setup.

-Richer