We had uba tuba installed on our kitchen island (http://maplered.com) and (http://maplered.com) Counter (http://GialloFiorito.com) tops. We also did matching Granite (http://tanbrown.org) tile for the backsplash. It was installed in July 2005. Is it necessary to seal it every 6 months to a year? Also, what is the best way to clean it? We have been using Counter (http://GialloFiorito.com) top spray cleaner by SCI? How do you keep it from getting a filmy coating on top?