Marble chips to get my snails enough calcium?

So my tank has one large trapdoor snail that I added on purpose, a few hitchhiker dozen bladder snails, and some pond snails. I like the snails and want to keep them healthy, the ones I don't cull anyway. I know they need some calcium in the water to be healthy, but I don't think my water has much naturally. I'll be adding some lava rock to the filter, and I was wondering if a few chips of marble in with the lava rock would help provide the calcium the snails need.

I also have guppies, and am looking to get bettas once my tank is finished cycling and stable.

 

Does marble have calcium? I haven't researched it, but intuitively I don't think it does.

 

Wondershell is a great product to help with calcium. I also find Nano Banquet blocks do well, too.

 

Cuttle bone, is what i used, consider adding unflavored tums to there diet, it's not hard to make snello.

 

Marble is made of calcium, since it's basically cooked limestone, but I don't know if it's biologically available. Thanks for the advice about other options. I'll have to look up snello.

 

Marble is the metamorphic form of limestone, so it does contain calcium. However, unless you water is acidic, it dissolves too slowly to to be of much use as a calcium supplement. You need a much softer material such as cuttle bone or crushed coral. Coral is aragonite which contains both calcium carbonate and magnesium carbonate as well as trace minerals. You can also add small amounts of calcium sulfate, also known as gypsum.