It feels slightly gritty but I cannot remove it manually or chemically. I worked diligently keeping my water balanced as you can see from my test results. I suspect this is damage to my fiberglass. When it is wet it looks okay but if it dries ( like when the water level drops) the walls develop a white haze over them. Really irks me as the pool is brand new! The fiberglass base color is black with cobalt blue and silver metallic flecks. Stunning, looks like deep ocean water. I fear over time it will appear less sparkly and less "oceany"and more like a black puddle. Oh well.