I THINK I have calcium nodules on the floor and icecicles on the walls, all over my colored pool plaster. I can't get a good photo of them so I borrowed a couple photos from Reddit that looks just like the spots and icecicles I have in my pool. They are white spots with brown around them, I'm pretty sure it's calcium but I need to know how to avoid this in the future and how I can treat the current nodules. I've done some research and a lot of people say this is from poor plaster work but we didn't have ANY of these spots until the 4th year, after our pool froze over this past winter. I always keep the water balanced and I adjust alkalinity based on temperature using the LSI calculator so I'm not sure why we could be getting these unless I'm keeping the hardness too high. I usually aim for 350 hardness as I was told by our pool builder that if we didn't keep enough calcium in the water that it would be leached from the plaster. I guess my main question is are these things from calcium in the water being too LOW or too HIGH? And beyond sanding these down one at a time (there's probably 200-300 of them) is there any way to easily remove these blemishes and try and keep them from coming back?