I don't believe its normal for your pads to sink in..what kind of pad are they and what size? I know the 5 inch pads are thin and you can see the dimples on the loop and hook side. If you have any pictures that may help us whats wrong with your pads. As for your white pads changing color its perfectly normal, I personally find the white pads the hardest to clean. If you run your pads under water and agitate the pads with your fingers and nothing comes out (polish, dirt, or any pinkish color) don't worry about it its probably dyed from the polish.