fiberglass shower floor cruddy-looking--how to fix?

[bws93222]

My one-piece fiberglass shower floor appears as if a thin discolored sealer/coating is slowly peeling away. No cleaning products will clear away this blotchy condition. I can sand away the discolored coating and it leaves a clean fresh surface. Is it okay to do this, or should I put some sort of sealer or something on top of the freshly sanded surface? I just need for the shower to remain serviceable and not disgusting to look at--I cannot replace it. Please advise. Thx.

 

[dextrous]

This may be a long shot, but it may be that whoever put the tray in forgot to remove the protective (clingfilm type) of plastic cover, which will peel off. The only difficulty will be getting the bits of film out from under the doorframe and sealant around the tiles. Don't use sandpaper unless you want to scratch the surface.