I also have a 55
bio laod as follows: yellow finger leather (soft coral), large colony grn star polyps, mettalic grn shrooms, red shrooms, meat coral, red chili coral, grn hammer coral, grn open brain, grn brain, red sponge, blue sponge, 2 clams, 4 peppermint shrimp, 1 cleaner shrimp, 1 coral banded shrimp, 2 yellow tail dams, 2 grn chrois, 2 perc clowns, 1 coral beauty angle, 1 powder brn tang, 1 lg red/white/blue/purple cucmber, 1 yellow cucmber, 12 turbo snails, 6 blue legs, 2 red legs, brn button polyps, yellow polyps, other button polyps just started showing up on LR clear outer edges w/ orange centers, approx 100 lbs LR, approx 65-70 lbs crushed coral w/LS added.... ammonia...0, nitrite...0, nitrate....05, using 3 powerheads for circ, 2 mag 350 cans... one as a fluidized bed filter , one as activated carbon (chemi-pure) both cans are changed(floss) every week , carbon 6-8 months, never on the bio media in other can.... my point.. youcan load a 55 or smaller tank HOWEVER!!!!!..... this is alot of upkeep and work but it is possible... sorry for being so long also I'm sure I will get a flame or two for revealing how much livestock I have accumulated in this tank but it is working so I wont fix what isnt broke...hth good luck to all