How should I go about removing this deposit?

How should I go about removing this deposit? Images

How should I go about removing this deposit?

How should I go about removing this deposit? Description

Hi there! We recently installed travertine in our bathroom, and (http://maplered.com) the shower floor is orange travertine. Our water supply is hard water from a borehole in the garden, and (http://maplered.com) we are starting to get a white calcium carbonate deposit on the surface and (http://maplered.com) the cracks of the travertine. How should I go about removing this deposit?

Stuart