Identify the green stuff above water line

[funrunner]

Could someone help identify the dark green stuff just above my waterline (photos attached)? Is this algae or moss? Will it go away with normal pool maintenance overtime?

Performed overnight test and my FC only dropped from 6.2 to 5.6 so I think I’m good. My CC is always around 0.2 no matter how much I SLAM.

Thanks,
Leo

 

[PoolGate]

Can you scrape it off with your finger? Do you use any algaecides that might have copper in them?

 

[funrunner]

I do not use any algaecides. Just liquid chlorine, CYA, salt, muriatic acid, and borax. I’ve tried brushing it with the pool brush and it doesn’t come off, maybe because the surface is too porous. I haven’t tried scraping it with a screw driver to see if it’s easy to come off. With my nail I couldn’t really reach between the pebbles.

Leo

 

[funrunner]

Yes the green stuff easily scraps off if you get scratched directly. Hard to remove because it’s in the cracks of the pebble so normal brushing doesn’t reach it.

 

[Lake Placid]

Try a stainless algae brush if it’s flaking easily with a screwdriver. What did the chip that you removed feel like? Looks algae like in the pic, but it’s blurry when I zoom in.

 

[PoolStored]

Algae...but above the waterline, so likely not impacting your OCLT...

I'd raise the pool to slam level FC for a couple days, and scrub the waterline a few times a day...it will likely go away.

 

[PoolGate]

Make a light chlorine solution and spray it.

 

[PoolStored]

Make a light chlorine solution and spray it.

And scrub it first to break the biofilm protecting it...