I have searched, read, looked, etc, and I can't find a definitive answer on what is happening to my pool. I even had a pool service company (highest rated one in the area on Yelp) come out and look, and he was stumped.
We bought the house in September 14. We did a water change earlier this spring. I received my TF100 not too long ago, and I've been using the TFPC method, which has been great! We recently switched from pucks to liquid bleach as well.
At first, I thought these were small specs of rust, as stated in my other thread. Some of the specs do, in fact, look like rust. I am having a hard time telling if they are all the same problem, if they go from redish/brown to black, or the other way around. At first, they were only on the bottom, but now I'm seeing them on the sides as well. They are pretty much on EVERY horizontal surface, including the top of the lights, steps, drains, etc., and now, they are even making their way onto the walls.
I was thinking it might be black algae since it seems to be spreading somewhat quickly, but I can't even scrape it at all with my fingernail to smear it. I actually can't even really feel them at all, they don't protrude from the plaster.
What I've done so far-
Vitamin C Test - no change
Held a puck on top of them - no change
Tried taking them off with a stainless brush - can't
Tried taking them off with pumice - some of them lighten up substantially, some don't at all
Current #'s as of today-
ALK 160 (in the process of aeration to bring it down)
Ph 7.2 (to lower ALK)
TDS 1100 (from pool store)
All of these pictures were taken this morning, before there was direct sunlight in the pool. One of the picture has my hand in it for size reference.
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