please help with my water stain

please help with my water stain Images

please help with my water stain

please help with my water stain Description

 have beautiful uba tuba Granite (http://tanbrown.org) Counter (http://GialloFiorito.com) tops in the kitchen.  One of my Counter (http://GialloFiorito.com) tops has a nasty water ring mark on it.  I have sealer that I bought at our local home depot  which I am not loving.  Is there any way to remove this water spot and (http://maplered.com) can you recommend a good sealer.  Also, how often should sealing be done (Counter (http://GialloFiorito.com) s are 5 years old).  Thanks.
Cindy Follman