Thinking of setting up a FOWOLR

[Reef Pilot]

Can't say myself, because have never tried that. But if you have enough surface area with your old rock work and bio balls with beneficial bacteria, maybe that is enough to provide an adequate nitrogen cycle for your organic waste. Then use a bio pellet reactor and with your skimmer you may be able to keep your nitrates low enough.

Why don't you give it a try and let us know how it works out. You can always add live rock later, or fill up a sump with it.