I've got a fiberglass pool that I've had for about 6 years. The pool bottom is supposed to be smooth. After opening this year I have noticed some areas in the deep end that feel rough, dry, or callus like a pumice stone. There is not an elevation change in the surface as one would expect with something built up on the surface. I seem to recall having a few small spots of roughness last year that scrubbed away and I thought was just crud that built up over the winter.
I've also found an area that is bumpy or pimpled as if someone had scattered coarse sand that stuck in place.
Is this scale build up? What can I try to remove this? Any thoughts would be helpful.