Argyll Eagle

I've grouted a large area of floor tiles using Bal Limestone Flexible Grout. Half of the grout has dried very white. It has been suggested that a white film of limestone settles on the surface, especially if the mix is very wet or when grouting is done when the room is very warm (grout drying quickly).

Any comments?

I have also heard that their is a substance which can remove this white limestone film.

Does anybody know what it is called?