Some people do put cuttle bone in the tank. I think it gets icky fast and hate the way it looks. I feed a variety of things, plus keep crushed coral in my filter and dose with liquid calcium. I feed 2 types of homemade food (a biscuit and a "jello") plus some canned or blanched greens and of course the snails eat leftovers from the cories shrimp pellets and any flake bits they find.
My biscuits are a mixture of pulverized dog food, shrimp pellets, pureed greens, eggs shell and all and hermit crab food. My next batch will have added calcium in the form of reptile dusting powder (Jurassi-cal is the brand). The jello is a recipe I got from applesnail.net that includes baby food, hermit crab food, fine chopped greens, dusting powder and knox gelatin. The jello is super simple to make and doesn't stink up the house like the biscuits do. If anyone wants the recipe I'll post both the original from applesnail.net and my version of it.