Nass. snails are great . A sand sifting goby is the best bet for the SB. Most say hermits arent good but dont add to many , they will just fight and kill for the best shell. Best if you add a bunch of empty shells to help prevent this. Some turbo snails but they tend to knock stuff over.
Most these guys ( besides the sand sifting goby ) are to help control algea out breaks.
Algea will always be around so the key is control by water quailty , flow , fish stock , not overstocking or overfeeding or adding to much stock to fast.