calcium carbonate is limestone pretty much it will raise hardness in ur water also provide calcium 4 beardies in small amounts it is however alkaline, another 1 to research would be calcium sulphate which is gypsum its nuetral ph but otherwise does the same in the garden and aquarium as lime, im just guessing here but the other parts would be valuble minerals, carboinate, sulphate . just bear in mind u will need to do more research and particulary to how much is safe/benefical as it would only be tiny amounts needd