What's left after Kalk is used up?

[Charlene]

What is left over after all the kalk is used up? Just wondering from a chemistry standpoint. Is there an inert powder or residue? What is it or will it all eventually dissolve?

 

[ReachTheSky]

It's mostly calcium carbonate, undissolved kalk powder or impurities that were in the powder used. Some of it might dissolve if you keep using it.