My Geneva is almost a year old and I've noticed that the shell (pearlescent champagne opal finish) is turning dull above the water line. I wipe it down daily, so it's not really dirty, just doesn't have the same luster as the rest of the shell. The top and below the water line look good. I've done 2 water changes. The first time I cleaned it with Windex and the 2nd time with Soft Scrub. Both cleaned but didn't really bring the shine back. The only other cleaner recommended by the manufacturer is baking soda. Haven't tried that yet. Question one: has anyone found what works best on this finish to bring back the luster? Question two: I've read on here that some people use Magic Eraser. I bought some, but the package doesn't say what chemicals they contain. I'm about a month and a half away from a water change. Are they safe to use with water in the tub, or should I wait until I drain it? Thanks in advance for the help.