Discolored plaster or stains?

[slangner]

I started noticing what appeared to be discolored pebble tec soon after my pool was complete. I chalked it up to normal discoloration. The first one was the large one in the picture. Within the last couple of months, the small round ones have appeared on the side of the ledge. My water is usually pretty balanced with the exception of high pH that I am constantly battling.

edit: The pool is filled with well water.

Has anyone had this problem before? Please help.
Thanks!

 

[Texas Splash]

At first I was inclined to say it may be something with the material or application process, but then you mentioned something about the overall chemistry and well water that have me thinking. So how about you do these two things for us:
1. Post a full set of water test results
2. Try rubbing a Vitamin C tablet against one of those stains and let us know if it does anything.

Also tell us if you or the installer has added any unusual pool store products other than muriatic acid, liquid chlorine, or stabilizer.