Roger's right. A bit of vinegar in a little warm water should dissolve any minerals on the chrome.
Here's another tip: As soon as the bar dries and you see any water spots, just take a dry washcloth and buff them off.
Half of the time water spots aren't minerals, they are soap scum. Wetting them just moves the greasy soap around, buff them off and they are gone.
If you ever want to remove the soap scum from a shower wall or glass door, get 0000 steel wool (that's the finest grade) and use it DRY to buff off the soap.
(It scares everybody the first time I suggest this)
But what happens is the pad gets filled up very quickly with what looks, and is, soap powder.
Use circular motions and just keep turning the pad over until it won't pick up any more, then get another dry pad and keep going until all the scum is gone.
You can use 0000 steel wool to clean the spots off of mirrors and chrome works too.
I can't emphasize enough that the wall and the pads have to be dry
for this to really work.
You can just throw the used pads away or, if you are really thrifty, take them into the kitchen and use them just like you would any other soap-filled steel wool pad.
extra credit: you can buff off the cigarette smoke film from brass lamps using the same drypad method.
Joe(0000 no scratches)Nation