sand sifting star vs. hector goby vs. conch

[troni]

i have a 20g about 2 months old. im looking for something that will turn my sand so it looks pretty.
nassarius snails do a perimeter and a zig through the middle also i noticed they just slide right over top of everything. my sand bed is fine to bigger pieces and this is what i used http://www.petsmart.com/product/inde...uctId=11147301

goby will eat detritus and turn sand and apparently eat good bacteria quickly. but also cloud my tank.

stars will just sift sand but apparently need a very live bed but also heard they dont.

conchs get to big.