Hi Bill,
For what you have I would do a mix of the following....
18 - Margarita's (Coralline encrusted)
18 - Cerith Snails (Baha Snails)
18 - Nassarius (If you have a sandbed)
18 - Baha Red Leg Hermits
This is a pretty good mix to start off with. From there you could tailor it to suit your needs a little more by what types of nuisance algaes are most predominant with conchs, sand cucumbers, sally crabs, emerald crabs, Scarlet Hermits, Black and White Hermits, etc.
Thanks,
Jeremy