Can this be black algae?

Yorkiegirl

Member
Mar 16, 2019
12
Huntsville, Alabama
I have a 35,000 gallon inground SWG vinyl liner pool. Pool chemistry is in line. This afternoon the FC was 7.8 and the CC was zero. PH was 7.4. I use a Taylor 2006 test kit. This evening I noticed black in the crevice around my steps. I used a brush and it peeled out rubbery black strips. It was mainly in this area with a tiny amount around the skimmer. My chlorine levels are holding just fine. I’m not noticing any drop off. Could this possibly be black algae? If not, does anyone have any ideas what it could be?
 

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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,726
Laughlin, NV

Smear it on a white sheet of paper. Black Algae will leave a green smear.

I do not think black algae would come off that easy.
 

Yorkiegirl

Member
Mar 16, 2019
12
Huntsville, Alabama
I tried to smear it earlier. It didn’t disintegrate enough to smear. It does seem to have a blue green tint to it in bright light. It’s sitting on the pool deck and I just looked at it. It dried into a hard much thinner “string”.