Designing Kitchens and Bathrooms - Calcium build-up on grout on shower floor

I have an accumulation of white, hard material just along the grout line along the base of my shower, where the wall meets the floor- not at all in the center of the shower. I assume it is calcium, but am surprised because we have a water softener, which is supposed to greatly reduce calcium in the water. It has built up fairly thick in some areas and is hard enough that you must "chisel" it off. Is there anything I can do to dissolve it chemically so I don't take the chance of damaging the tile or grout trying to remove it? What can I do to prevent it from re-accumulating once removed?

Thanks for any help
Mike

CLR Calcium, Lime, and Rust it is a product found in all the grocery stores and big box hardware stores.

Thanks for the advice. I'll give it a try.
Mike