What is this black in my pool?

[ssgumby]

My pool is about 8 year old, I built it myself. Over the past couple summers I keep getting black spots in the pool. This year it is taking over. Almost impossible to get off. If I get in and scrub extremely hard it will dissolve into green dust.

I did SLAM before with no results (last year). Seems nothing gets rid of the black other than brute force.

CYA 80
PH 7.6
FC 5

 

[mknauss]

Black Algae

This guide provides a step by step procedure for eliminating black algae in your concrete or gunite pool. Read full post here.

www.troublefreepool.com

Have a read through the article.
It is very unusual to get Black Algae on a vinyl pool surface.

 

[ssgumby]

Black Algae

This guide provides a step by step procedure for eliminating black algae in your concrete or gunite pool. Read full post here.

www.troublefreepool.com

Have a read through the article.
It is very unusual to get Black Algae on a vinyl pool surface.

I have read that and think I do have black algae. I am getting my bottom redone and new liner this fall. I DIY my pool and the bottom was NOT smooth, has lots of little divots. I think that is how black algae is setting in .. I am going to get the bottom reskinned.