Saltwater Without Liverock?

[360º]

i've seen peoples setups in person and online where they have a SW tank without any liverock.

they use river rocks or lava rock.

how is this even possible?

[iDream]

its a FO (fish only) tank, they just don't have biological filtration (not as much atleast) and rely on mechanical and chemical filtration.

personally i like the look better so i'll always have atleast a FOWLR tank

[Wy Renegade]

The correctly chosen lava rock can give you biological filtration almost as good as true porous ocean rock. However, I would hesitate to use it more from concern with leaching issues. River rock on the other hand, as stated gives little to no biological filtration and IMHO just doesn't look right in a SWF tank anyway.