I would use a variety of snails, smaller Trochus/Turbo species, Astrea (there are some species that can right themselves when flipped over on sand), nerites, ceriths, nassarius(carrion eaters), stomatella, collonista(mini turbos), and collumbelid(listed as strombus grazers from Indo-pacific sea farms) snails. The last 3 species reproduce readily in home aquaria.