clean up crew requirements

[dunl]

I have a 54 gallon bowfront, and I'm looking for suggestions on what and how many clean up crew I should have.

Currently in the tank I have a yellow tang, 8 small green chromis, mandarin goby, lawnmower blenny, 1 cleaner shimp, 1 small crocea clam, 8 algae eating hermits from Big Al's in Calgary (not blue or scarlet legged, so no idea what kind these are), and 5 turbo snails. Also have a hammerhead coral and 3 purplish mushrooms.

I'm open to swapping current inhabitants if it seems necessary.

Thanks,
Dunl