Black Algae in Above Ground Pool?

[violet-mermaid]

Is that possible? My pool was doing SO WELL over the summer and now I am seeing black spots on the bottom (that are hard to brush off) after about a week of not being in it. It's definitely my fault for not staying on top of it- we've been so busy. I read that it usually appears in plaster pools and requires a steel brush to remove. Since my pool is vinyl liner- what's best to do?

 

[Donldson]

Have you added anything other than chlorine and acid to the water this year?

 

[violet-mermaid]

I did add stabilizer at the beginning of the summer. Tested CYA today and it is at 0. Chlorine was at 0 and Ph was 8.2. Added acid and chlorine, numbers are good now. On my way in a bit to get stabilizer. Anything else I can do besides brushing?

 

[Donldson]

Since you're seeing algae and can confirm that you had zero FC I'd start the SLAM Process. Assuming that this is organic that should clear it up with the elevated FC and brushing, and seeing it through should get whatever it is out of the water so it can't resettle on the bottom.

And to answer your earlier question, definitely don't use a wire brush on vinyl. The results will look worse than any algae. Brush it with a regular brush during the SLAM and that will help the chlorine get in and kill off whatever it is.