I was wondering if anyone had any idea what these knots are. I'm not sure how else to describe them. I bought a house in January and it came with a swampy concrete pool. With the help of TFP, I now have a sparkling clear pool. Now that I can see the bottom clearly, I noticed these knots along the edge of the pool. Most of them are in the shallow end (3'6" deep) and by the skimmer (4'6" deep).
A little history about the pool as I have been told by the previous owner:
It was built roughly 1950's
The previous owner drained the pool every single year because he said it was easier to start with fresh water
It has about 3 different paint layers of different colors...meaning he painted over the old paint each time
The shadow at the bottom of the pool in the post TFP method pic is actually a painted killer whale
This is an image from the appraisal showing the swamp
This is the pool now post TFP method
These are the "knots"
If anyone has any idea what they are and if I should be concerned about them. I definitely don't want them to get any bigger. I do plan on doing a pool renovation next year but for this season I just wanted to be able to swim in it.