Not Eating Calcium
If your snail isn't eating cuttlefish there are a few things you can do.
The first method is to wean your snail onto it. In a lot of cases, particularly wild-caught specimens, they simply haven't figured out that cuttlefish means calcium. Try crushing the cuttlefish and sprinkling it over other food, perhaps even covering some of the substrate with it. The snails will eat the food, discover the cuttlefish since they can't separate the two. Then you can put pieces of cuttlefish in dusted with cuttlefish powder. Your snails will recognise the powder and in doing so discover the cuttlefish. In most cases this works fine.
Some snails still won't eat it off the block even with the above method and because it is likely that natively the snails eat foods high in calcium we need to make sure they get enough. This requires us adding the calcium to other foods. There is a study about the growing rates of Archachatina marginata and calcium sources. 20% Calcium carbonate was deemed the best amount, but it is undetermined whether this resulted in the healthiest shells or the fastest growth. 20% seems awfully high when you consider that fruits high in calcium such as papaya contain only 0.04% calcium. However, snails are known to live in calcium-rich soils and areas with a lot of limestone or natural chalk. This indicates they do get calcium from other sources:
Note: Having recently encountered a problem where a snail suddenly stopped eating cuttlefish and damaged its own shell quite badly, a diet of a mix consisting of various cereals and 50% powdered cuttlefish soon sorted the problem.
For alternatives to cuttlefish bone, solid, liquid and powdered click
here.