Apple Snail Shell Health

[questomatic]

I have a 5g tank with 4 fancy guppies and 3 small apple snails. Recently I have noticed that the shells of the snails have lost their smooth pearly look and are developing pits and cracks. I bought a Weco WonderShell for 5g tanks but I am hesitant about throwing it in as the directions and information on the package are limited. Will this product be safe for my fish? Are there other remedies for this issue? I'm assuming this problem is a result of too little calcium in the tank. What experiences have you had with shell health for apple snails and how have you remedied them?


Amber