The title is sort of an oxi-moron. But for reefs I know there are far more chemicals used to keep the system steady, apposed to that of a FOWLR setup. I was wondering if there were, I guess it would be called, treatments?, (since They are natural?) I could use to have a more natural environment for the inhabitants? I'm not a big fan of using chemicals. For example, for my tank, I use an all natural powdered calcium substance for my tank, to help with coralline growth, rather than the liquid 'chemical mixture' found in the bottle on the shelf next to it(at my LFS).