BajaPoolRepair

Lots of professional advice here... but everyone was quick to remove layers after layers of your plaster, only one person hinted that your "stains" may be just "lack of" plaster. And what your seeing is the gray concrete behind the plaster. And if your plaster is that thin, after acid washes or years of service, or mistreatment of chems... then another acid wash or diamond sanding will ruin the whole thing.