Ok, so all tanks have pods? My tank isn't exactly a reef yet, just live rock, crustaceans, and i did have fish but they all died. So all live rock has pods? Also, what else should i have in the tank.

Also, the reason why I'm gettin the refugium is to lower my nitrate levels, how does it do this? Right now my seaclone 100, and 3 biofilters are what is filtering my tank, will the refugium be able to filter well enough so I wont need my bio-filters anymore? Do, i need more than live rock to filter my entire tank? And how exactly does the refuium fitler??

Additional Info: 55 gal tank, starfish, 15 hermit crabs, 15 snails, coral banded shrimp, emerald crab 50 lbs live rock.