I started moving away from hermit crabs as well, as mine die I am not replacing them. I am going with all snails, Cerith, Nerite, Nassarius, Turbo, and Astreas for me. Some of the sites that sell inverts on line have recommendations for number of this snail per gallon, but I just mix and match and put in how ever many I like. If, fingers crossed, I ever run out of algae for them to eat then I will supplement their feedings, but right now that isn't a problem.
Just the other day I did see one of the
Bumble Bee snails that I bought when I set up my first saltwater tank about 3 years ago. I thought that was a pretty neat thing.