I have a one-piece fiberglass tub/shower unit, which is approximately 22-25 years old. About a year ago I started using a bathtub mat with the suction cups (to prevent it from slipping). A few months ago I noticed what I call "pebbling" (not blistering as in another posting, since there is no liquid coming from these) on the surface of the fiberglass in the area where the suction cups were. Not being very smart, I continued using this mat until recently when I noticed that I now have small chips (less than an 1/8 of an inch) coming out of the surface, the surface being an off-white or bone, and a dark sub-surface. Has anyone seen this happen? Would it be better to replace or repair? I think I am near the end of the fiberglass lifespan, but I don't know if this is costmetic or if it indicates something more serious. Replacing would be nice, but it is a very small bathroom and it is a one-piece unit, I guess it would have to be cut out. There are no cracks that I can see. Can water seep through fiberglass without the glazing (through the chips)? Thanks