hey, i just got a 30 gal tank, and i want to set it up for saltwater. i have 4 freshwater tanks rite now and have been doing fresh water for a long time, but now i want to set up a marine tank. i was thinking of using a backpack filter with a biowheel thing, but i dont really know what would be best. i dont want to do coral or polyps, just some sea grass, fish and inverts such as shrimp, crabs, maybe a tubeworm or two. does anyone have any suggestions or ideas?