Difficult Differentiating Black Algae from PebbleTec

[Dennyhle]

So my salt cell is dying I believe because 2 independent tests showed a salt level of 3000 and my chlorine generator says I only have 2200 sometimes and will stop generating. My water is still pretty clear but I noticed some green algae along the walls and hundreds of small "colonies" of black algae. The black algae colonies are like 1/4th the size of a dime or smaller. They are clustered in the worst spots like at the 90 degree angle between the pool wall and steps. Anyways, my pebbletec floors also has black specks in them so its kind of hard to distinguish if its the pebbletec or black algae at some spots especially on the deeper end of the pool. The ones on the shallow end I have confirmed by touching and examining it. Any advice? How do I know when I'm done?

I've read through the Black Algae guide and am starting the SLAM tonight. I tried scrubbing the black algae today but I barely noticed any difference. I'm guessing it just takes time for the chlorine to kill it after you scrub off its protective barrier. I have my own (good) testing kit but the pool store also found that I have 450 of phosphates. Is this something that needs to be treated?

 

[Mdragger88]

How do I know when I'm done?

You are done w/slam when u pass ALL 3 end of SLAM Processcriteria.
*Crystal clear water w/no visible algae
*pass Overnight Chlorine Loss Test
* cc’s 0.5 or less
Then u follow the black algae guide. This involves keeping fc elevated while u work on the areas individually.

Black Algae

This guide provides a step by step procedure for eliminating black algae in your concrete or gunite pool. Read full post here.

www.google.com

 

[Katodude]

Black Algae is different. A standard SLAM will not work. You will need to break the biofilm of the algae in order to kill it and standard brushing will not do that.

If you only have a few spots, I recommend getting a mask and snorkel and getting down there with a small SS brush to brush at the algae. If you have a lot of black algae a weak pressure washer might be useful to blast it up. Be very careful not to damage your plaster. If you see a pebble or anything like that come loose stop. I also use a bamboo bbq skewer to pick at the spots.

After which get a 1 gallon pump sprayer and get into the pool and hit the newly cleaned areas with a blast of high dose LC.

During this time keep you FC elevated to 20% of CYA. If you clean all the black algae you might as well get to SLAM level for a while.

 

[Klutz14159]

Can you take the whole pump sprayer into the pool or does that part have to stay out of the water? (sorry, I have never used those before)

 

[Katodude]

You can take the whole thing in.