I'm not sure if it's been asked before by I couldn't find it when I searched. I'm converting my tank from SW to FW so I have a lot of extra stuff I wont need, like Live Rock that is now dead rock. My question is if cleaned properly wouldn't this rock make for good filtration? It would be similar to using ceramic media, especially if you break the rock into rock rubble. I have close to 150lbs of it so i was thinking of filling the media section of my 55g sump with half sponges, half rock and I would incorporate filter pad/floss into the system as well.