Making an assumption but are you running a biocube? If so we have the same tank. That is WAY too many hermits. I have 5 in mine total. 3xblue legs, 1 zebra hermit (I found him half dead in a used tank I bought), and 1 massive scarlet hermit. I might have 50 snails in there though. My nassarius breed like rabbits, I put 5 in prolly have 15 now. I have 10 (at least) astrea snails and arpund 20-25 dwarf cerith snails. Oh and a sand sifting conch. And a turbo snail of some type I’ve never seen who frequently buries himself.
i woildnt get another hermit of any type. I personally love cerith snails. They’re the best snail honestly as they’ll eat anything algea related. And they burrow so they clean your sand. If I were you I’d do the nassarius you thought about, a few astrea, and a whole lot of cerith snails. Nothing beats ceriths. They reproduce in my tank, eat red slime, maul gha, and burrow so the hermits rarely can bother them.