I was in the process of fixing a corner of my pool and i had to drain the water 2 feet. I discovered that on the pool walls there are what looks like calcium build up. It seems like it forms and top of small hair line cracks.
The guy from the pool company that plastered the pool 3 years ago, said that it is because my water is LOW on calcium and it is leaching calcium FROM the plaster.
Does it make sense?
As far as I remember, my water was about 300-350ppm and it was on the high side. I try to maintain PH of 7.2-7.6 range. Granted at winter time when water was about 50-55F, I might have let the PH to go to 7.8 or so.
I'm attaching some pictures for you guys to take a look at.
If that is the case, is it good idea to use Shock as i have plenty of it in my garage, and i know that using it will raise the calcium level which is usually not that great. I need to clear the pool up from some green water formed as i was not running the filtration during a week when the pool corner was getting fixed.