I just opened my pool and for the most part it looked great but I had some very localized patches of scale. There were 3 or 4 places around the pool where "lines" if scale have formed. They are all very similar to the attached photo - between two tiles near the surface. Last year I only had one, but this year there are a few more.
Does anyone know why this is happening in these spots and how I should remove them? Is there a way to prevent more from forming next year?