Start small on your cleanup crew. If your going to get hermits make sure they are scarlet reef hermits. Very laid back crabs that don't kill snails and each other for the heck of it. I think five snails, a couple ceriths and 2 or 3 scarlet hermits should do nicely. Add some more later on if you think the ones you have can't keep up with the algae. But otherwise buy only a few so they won't starve to death. These monstor packages that on line vendors say you need is a crying shame, such a waste of inverts lives. As everyone said, it's fine to keep two shrimp in a 30 gal in fact it's best so they will always have fertilized eggs.That in turn feed fish, inverts and corals. Scarlet skunk cleaners are hermaphrodites so no need to worry about pairing them up.