I started getting some stains on my plaster late last year. The stains started with one then others started popping up and now I have around ten of them. Each is shaped just like the Star Trek logo that was used on their shirts in the TV show. They do not respond to Vitamin C or a chlorine tab. They are not rough to the touch. I am starting to get worried because more and more are appearing. My current test from yesterday yields
PH 7.8 ( I know it is a little high but I ALWAYS keep it between 7.4 and 7.8)
CYA 55 (Both tries were right between 50 and 60, I know it is a little low but we have had a LOT of rain)
I called my pool builder last week. He sent a guy over within two hours but the guy seemed stumped. He asked if we had used the metal out that was provided when the pool was built and I told him I had. He asked if we were adding more every month and I told him I had not. I told him I tested for metals every six months at a local pool store and had never had any metal present so I did not see any need for it. He said that since there was metal in the gunite I should be adding it and that may be the cause of the stains. I told him that since the plaster was supposed to be waterproof how could rebar in the shell bleed through like that. He had no answer. I also have one small spot of plaster about the size of a dime that has turned completely white on the grey plaster. He took some pictures and said he would show the owner and get back to me. It has been a week but no response. Any ideas out there?
The stains are all shaped just like this and are light brown.
Here is an image without modification and you can see one on the top left and the bottom right. You can also see several smaller ones in the center but they have the exact same shape.
Original Pool spots.jpg
This is a close up shot that has been modified to improve contrast.
Original Pool spots enlarged.jpg
Thanks for the input!