Dark specks in one corner of pool

[GreatCanadian]

Could these possibly be algae? My numbers are:
FC=5
CC=0
TA=70
pH =7.5
CYA=50

FC has never fallen below 3. These specks are confined to one corner of the pool. They are black or a very dark brown and very difficult to pick off with a fingernail. They do not feel the least bit slimy at all. Could it be algae? I cannot guard my pool any closer than what I have been. How could algae have possibly formed, if it is indeed algae.

Edit to add: Cannot be brushed off with the bristles on a Catfish pool vac.

GC

 

[linen]

It doesn't sound like algae to me. If it was black algae, my understanding is your can scrap the "head" off and they are usually green on the inside.

Could you post a pic?

 

[GreatCanadian]

Yes, if the weather gets a bit nicer later today I will get in and take an underwater shot. The specks are so small I doubt they'd show in a pic unless I am right on top of them.

 

[GreatCanadian]

Finally got a chance to get in the pool today and snap a few pics. I also tried to brush them off again with a stiff bristle brush. Just a few spots came off. The rest could not be brushed off:

Any thoughts? These specks appear nowhere else in the pool, only this corner.

 

[central nj]

I have something similar, just went to shock level. Hope someone can give a definite answer.

Steve

 

[GreatCanadian]

Can you brush yours off? Or scrape them off easily with your fingernail?

 

[central nj]

GreatCanadian, Absolutely not. I'll let you know if the shock gets it off.

Steve

 

[GreatCanadian]

Thanks. I would appreciate you letting me know. Tested water again just a few minutes ago. All levels are good.

 

[GreatCanadian]

Bump.
The specks are still there but have not increased or decreased. It must not be algae.

 

[linen]

Hmmm....I wonder what they are? Could it be hardened tree sap?

 

[GreatCanadian]

Holy Crud!! Brilliant!! Built a new deck. And that corner is where the ladder is. I drilled holes there to nest the ladder in. Some wood chips or sap must have made its way into the pool. I bet you are correct sir!!