I'll have to look into water testing kits at some point. We've got a water softener at home, I've always wondered how much calcium it actually removes, and how much something it puts in - the softened water tastes awful, I think the manufacturer tells you not to drink it too.
Salifert Ca Profi test for Calcium, usually used for aquariums and Salifert KH/Alk for carbonate/alkalinity are the main ones.
Ashbeck is the usual brand of water home brewers use if their water is problematic - cheap as chips and known water profile.
This is a good read for how to test and what to do with the results.