Is this calcium buildup?

Any input on this? No idea what it is I was able to scrape a bit of it off to expose the bluer plaster below. It has appeared about 1.5 months after pool build. Chemistry has been good since, calcium has been somewhat in the low end around 200-280 during that time point.
 
Looks like calcium nodules...


@onBalance may have thoughts.
 
The one spot that I see in the middle of the photo seems to be a small defect in the plaster. Perhaps sanding with some wet&dry sandpaper will rectify it. The calcium level of the water is not a player in this particular spotting problem. Are there other spots in the pool?
 
The one spot that I see in the middle of the photo seems to be a small defect in the plaster. Perhaps sanding with some wet&dry sandpaper will rectify it. The calcium level of the water is not a player in this particular spotting problem. Are there other spots in the pool?
Yes this one is the most major one about ~3"-4" in diameter. There are smaller spots around 1"-2" in diameter in a couple of more spots in the pool.
 
If they are calcium nodules, then each spot or nodule would have a raised rough deposit above the surrounding smooth plaster surface. Is your pool new, or is this a re-plaster job?
 
Then it is not likely that the problem is nodules forming. Are the spots fairly smooth, or are they raised and rough?
Keep an eye on the spots and see if anything changes over the next few weeks.
 

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