Is this black algae?

[aznfayeth]

Does this look like black algae? A week ago, our swg timer malfunctioned so there were 2 days with no chlorine. I've noticed this brownish stuff on the floor but I thought it was dirt. I poured in some pool clarifier 2 days ago so that's why it's clumpy. I'm going to do the overnight fc loss test tonight.

fc: 7
cc: 0
tya: 50
cya: 0

 

[Bama Rambler]

Doesn't look like it to me.

Since you added clarifier, you need to vacuum to waste if you can.

 

[aznfayeth]

OC FC loss test is 0.5 at night, 0.25 in the morning. The black stuff grew back even though we kept vacuuming it every day.

 

[Bama Rambler]

Are you saying that your FC was 0.5 ppm? If it was the test is invalid because your FC should never be that low to begin with.

You need to perform the shock process until you pass the OCLT.