Mustard Algea or Pollen (photo attached)?

[ToddGak]

A few weeks ago, my pool water got cloudy and I noticed some green on the stairs, so I did a SLAM, which took about a week to complete. Shortly after completion, the water got a little bit cloudy again, especially after vacuuming (I could always see the bottom though). I did nothing other than maintain normal chlorine and pH levels for another week or so. Now the water is clear, but there is "stuff" collecting in streaks on the bottom, along the perimeter of the pool (see attached photo). It's like it precipitated out of the water and collected there. There is nothing growing on the sides of the pool.

The "stuff' is dark in color, brownish, but looks yellow where there is less of it. Do I need to do a SLAM with mustard algae level at the end, or vacuum to waste and hope it was just debris/pollen?

Thanks

 

[woodyp]

You should perform an Overnight Chlorine Loss Test to see if is algae or not.

 

[ToddGak]

Yesterday I vacuumed. In the evening I added chlorine and before bed I started the OCLT.

When I was done vacuuming, the water was cloudy. I assume from a combination of the vacuum brushes kicking up debris (though I went as slowly as I could), and some of the debris making it through the sand filter and back into the pool through the return.

OCLT showed no loss of chlorine overnight.

 

[frogabog]

I don't exactly get the no FC loss overnight, but those pics sure do look like algae.

What are your test results? I only see chlorine additions in Pool Math. Could you post a complete set of results?

 

[ToddGak]

FC: 9.5
CYA: ~45
pH: 7.4
TA: 70