Question re: Live and/or dead rock in sump?

[newreefer_59]

My tank is up for about a year now. I still have nothing but a skimmer in the sump and wondering if I should place some aregonite, live rock or some dried out old coral pieces (I have some large pieces in storage) into the sump, and if so, which compartment. As per pic, the left had side has the skimmer elevated about 3 inches off the floor and it runs well there. All I have in the right compartment is the return pump.

Thanks!