Black Algae or not ?

[sicric]

Algae has never been a problem as I have kept on top of my chemicals ( hardest to do in summer in AZ). Only time (5 years ago) I had "green" algae was when my salt cell had blown a fuse and that only lasted less than a day. I'm getting these brownish dots in various areas in my pool which are fairly easy to rub away with pumice stone or similar. They're areas which get a lot of direct sunlight and once I get rid of them in an area, they do not come back there. The spa, which is slightly raised up in a corner and has a lot more shade than any other part of pool, has never had these spots.) I have never had these spots until this year, pool WAS drained and refilled early in year. Biggest area has been about a square foot (never more than that) and usually much less. I've kept my chlorine level slightly higher than normal for about 10 days now. Weather here has been extreme for that time even here in AZ. (110 degrees+ , with a few 117+thrown in there, for 10 straight days, at least). How can I be sure what exactly it is and does it sound like black algae ? My basic numbers are as follows;
FAC = 7.0
TAC = 7.0
SALT = 4000ppm
CYA ppm= 80
TA ppm= 100
pH = 7.8
Copper ppm= 0
Iron ppm= 0
Phosphates ppb = 90
Calcium Hardness = 250

 

[kimkats]

Can you scrape some of it off with your fingernail? If you can, rub it off on to a white paper towel and let us know what color it is.

Kim

 

[sicric]

Can you scrape some of it off with your fingernail? If you can, rub it off on to a white paper towel and let us know what color it is.

Kim

Is this where I say haha.......just kidding, I think (If it were to rub off black then its black algae :-?).......actually at this point the only visible dots are too small to scrape with my fingernail. I thought I gave enough info/facts to all the "Swimming Pool Walter Whites" out there that they could tell me if it's even at all possible that it could be black algae. How does one even "get" black algae. My neighbor 2 houses down had it bad, but that was from neglect (started green) chlorine level was zilch for an extended period 2 summers ago. I do get a fair amount of leaves in my pool from neighbors tree over hanging slightly over the spa but I am on top of that also. Other than that my water is crystal clear and the numbers have been very consistent all year since the refill. I'm running my filter & SWC 20 out of 24 hours the last 2 days. Should I continue this. $$$$

Thanks

 

[kimkats]

But I was being serious. This is the tried and true method.............if it is black algae it will be green when you rub it on the white paper towel.

Now how you got it/get it? Who knows???????? Here is our link to getting rid of it:

Pool School - Black Algae

Do you think it will show up on a picture?

Kim

 

[JamesW]

Note that black algae is not black (usually) or algae.

It's actually a bacteria called cyanobacteria. Cyan is a color that is blue/green. So the name means blue-green bacteria.

A picture would help.

 

[sicric]

thank you for the info, I will try to include a pic next post....and will ask for advice if it IS NOT black algae