Live rock in Freshwater?

[knifegill]

Just look up freshwater deep sand beds. They're simple and effective and used by many hobbyists. Worms and snails are used to transport nutrients down to the anaerobic layer. This is not a theory or guess, anaerobes are easy to cultivate in freshwater. Ever walk past a pond and see those bubbles coming up? That's it.

 

[carsona246]

One thing you should count into your equation is the fact that a) reef tanks have huge water movement and b) they're stocked lightly with a lot of live rock. In other terms, if you are going for a fish tank with a high bio load (I'm assuming this is why nitrates are problematic?), your plan is going to fail, similarly as live rock filtration is usually not the only filtration employed on large FOWLR tanks.

While this is true, live rock is often the only filtration method employed in saltwater tanks as well. Again, I'm not actually trying to solve any personal tank problems, my tanks are perfectly fine. But I don't see why more people aren't curious if this works, especially if it means adding some rocks to a tank could reduce nitrates.