Black Spots on pool - is this Black Algae?

[tjf120]

Is this black algae, or could these small black dots be from a bad chemical addition? You can see the size of a jet in the picture for reference. They are really small black dots.



I'm new to the forum, I'll be doing a couple other posts about pool chemistry.

Here is a pic of the pool, overall, the pool seems in ok condition, my 'simple' test kit the basic properties or OK. Taylor 2006 kit should be in on Saturday, and will post results.

 

[257WbyMag]

Hard to say. Do they feel slimy? Have you tried holding a chlorine tablet to the area involved to see if they fade with this treatment?

 

[tjf120]

Do not feel slimy. I did try the chlorine tablet yesterday, no change to the spots today.

 

[Butterfly]

Can you scrape some off and rub/squish it on a white piece of thick paper. If it stains green (even dark green), then it's algae.

What type brush do you use for the pool?

 

[tjf120]

I should have said, steel wire brush scrubbing. Is it ok to always use the wire brush for the pool? Don't see the purpose of the Nylon brush. It is a gunnite/plaster pool in Houston, TX

 

[Butterfly]

I should have said, steel wire brush scrubbing. Is it ok to always use the wire brush for the pool? Don't see the purpose of the Nylon brush. It is a gunnite/plaster pool in Houston, TX

Yes, you are correct using the wire/S/S brush. Anything else would just make black algae mad - um, it does look like BA to me.

Can you scrape some off (maybe fingernail scrape off) then squish on the back of a business card/hard paper and see the color?