You can scrape the cuttlebone with a knife and put the dust in there.
But do you know what your water pH is?
what your TDS total dissolved solids or gh/kh general hardness/carbonate hardness?
Those things might help you get the correct amount in there if needed at all.
My snails munch on the cuttlebone once in a while. Yours might be doing it too. Softer /acidic water will eat up the shells.
There is a shrimp mineral supplement too. Fluval makes one, and there are a couple other companies. Basically is the same as adding some crushed coral to the water. You will end up increasing the pH.
So make sure it is ok with the other stock you have and add it gradually.
Then you will need to figure out how much will be needed to add/replace the supplement when you do a water change, so like per gallon or per 5 gallon bucket, so you don't mess with the fish/tank parameters.