chalk as calcium source

[tawauboy]

anyone tried using chalk as source of calcium?
chalk as in black board chalk...
chalk is calcium carbonate, right?
any idea of other 'unwanted' stuff that has gone into the production of chalk?

[Allen_1971]

I'm not sure about that... if you're talking about old chalk when I was in school maybe... nowadays a lot of chalk is marketed as being "dust free" which make me guess that there might be some additional binding agents placed inside. If you need to dose calcium, I'd stick with either equilibrium (expensive) or calcium sulphate (cheap)

[juggler]

I think chalk is quite hard to dissolve in water, right?

[tawauboy]

yeah! just toying with the idea.
the 'dust free' marketing label does cause concerns.

let's say that chalk is just chalk and nothing else.
and it is difficult to dissolve in water.
would the weak carbonic acid due to co2 injection help to dissolve the chalk?

and if snails have good shell, does it mean that there is no calcium deficiency?