I took a sock filled with Vit-C tablets and drug it around. See streaks at the bottom.
I must have one heckuva lot of iron in my pool because it looked no where near this bad when I first opened pool 2 weeks ago. The troublesome thing for me is that I've used a lot of sequestrant. An entire bottle of Sequa SOL upon closing pool in fall.
Used over a bottle of a product called Staintrite (recommended by pool store) when I first opened pool two weeks ago.
Since then, have used a half-bottle of GLB Sequasol in the last week. So, despite all the sequestrant use, the stains are still rapidly formulating.
After first opening pool, there were only a few of these brownish stains. As you can now see, pretty much the entire bottom and sides are stained.
I must have an out of control iron problem in the water. I'm sure it's the heat exchanger which was replaced last year. That's when stains started appearing.
As you can see, my pool isn't going to win any beauty contests on the TFP introductory picture slide show.