I'd say, start slow and work your way up. Don't add a crew in the numbers you see in online packages. Once your tank is cycled, throw in a dozen or so astrea snails
, a few nassarius for the sand bed, and if you like 10 or so hermit crabs. Wait a few weeks and see how they are doing. If they aren't getting the job done, then add a few more snails slowly.
A lot of people don't like crabs, as they get violent with the snails at times. What you can do is buy a bunch of shells at your lfs or on ebay so they are less likely to kill the snails.
Also, I can't stand turbo snails.... they are a cold water species (usually), so they don't live long. Plus, they are like a bull in a china shop... always knocking things over and being a nuisance.