I LOVE my CUC!
I have snails, lots of them...they are a variety of Nassarius, Turbo, Margarita, Cerith and Nerite (each feeds on certain types of algae). I also have peppermint shrimp and a hectors goby to eat the extra wasted food....Seahorses are very messy eaters.
When I had my tank set for corals I also kept serpent stars, and peppermint or cleaner shrimp, and hermit crabs...even a few emerald crabs and a Sally lightfoot. I loved my fan worms for the filter feeder to help with keeping the water nice and clear.
I have never ever had to vacuum my sandbed (not even on my seahorse tanks). Maintenance consists of water changes, and harvesting macroalgae. Along with the mag float to make sure the front glass is clear.
As a reef, my rocks never had to be "blasted" with a turkey baster, because they were clean as a hounds tooth....but I do believe that was because I aimed my PHs correctly to keep them clear of built up detritus. Sigh, I miss my Koralia PHs, seahorses hitch to them, and I don't want any tail injuries.
Jay...if anyone had a dozen dead snails, the smell is the least of their problems, because if the snails are dying by that number something is bad wrong with the tank. Live rocks means lots of eaters of the dead, and serpent stars are great for cleaning any dead critter in the tank BEFORE it could smell. If you had a proper cleaning crew your dead snail would only be an empty shell, and no bad smell. Our CUC critters eat more then algae.
Snake, you are correct about adding a bunch of snails when there is nothing for them to feed on. A good CUC is built slow as the need arises.