How to remove water mark from travertine?

Can you please tell me how to maintain travertine flooring.  I have also noticed that if a drop of water is not wiped up immediately it leaves a permanent mark.  Is there a product you recommend to remove these?  My kitchen and (http://maplered.com) all of my bathrooms in the home I just moved into are travertine.  They were sealed before moving in, but water still leaves a mark.  Any advice on routine maintenance and (http://maplered.com) removal of these “spots?would be appreciated.   I am convinced travertine is not a good product in a kitchen!