If the mandarin is the only fish that will eat pods, in a very well established 30 with supplemental feeding, it might make it. No guarantee. I wouldn't try it, and if there are other fish that will compete for pods, I definitely would not attempt it.
Lace rock can be used in combination with live rock--the encrusting algae and such will colonize pretty much any surface they can, and the porous rocks will also harbor the good bacteria.
Lace rock can be used in combination with live rock--the encrusting algae and such will colonize pretty much any surface they can, and the porous rocks will also harbor the good bacteria.