When I opened my pool this year, there were a lot of brown stains. None of this was there when I closed the pool late September. Thought it was algae, but it wouldn't come off. Finally I drained the pool and took some pictures (below). I have applied bleach to these areas, the stains laughed at that. Tried MA, no real lightening there either although it did fizz.
I have also noticed these stalactite like formations on the vertical surfaces and nodules on the floor. Do I have a calcium deposit issue? Looking very closely at the brown stains they look more like mineral deposits than stain. Really would appreciate some help because I am at a loss.