My new plaster pool is COVERED in green stain..

[sunofthebeach]

do you have any of the"algae" left? Can you post a picture?

It is hard for me to believe your pool installer did not know what algae looks like.

I do like your style hausfrau, charge forward and try anything and everything.

If it were me I would go out today and get a test kit, even if it is a $5 chlorine and PH kit from Walmart. I have rough, pitted in some areas plaster because I did not pay enough attention to the PH and Calcium.

If what you really have is Algea, you are going about it wrong goofing with the muratic acid. I am sure acid will kill algea, but you probably harming something else.