Is this algae?

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L

loveit

0
Bronze Supporter
Aug 31, 2015
26
walla walla, wa
I have some black looking stuff on some of my concrete and the track of my auto cover. I did the scrape test on a white piece of paper but couldn't get much on there. It didn't leave green behind, but brown. We do have some lawn treatments but I'm not sure what they use.

Before reading about that scrape test for black algae, I just assumed it was dirty and started cleaning it with a soft baby toothbrush but once I saw just how much "gunk" was coming off, I stopped so I could try to find out what is going on.

Here are the results from my tests today:
Chlorine 3
CC: .5 (?)
PH 7.8
CH: 300
TA: 120 (high)
CYA: 40 (low?)
 

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This is above the water line so it wouldn't make any impact on your test results. Spray some bleach into your coping cracks to see if it kills it. I get dirt accumulating in my coping cracks too.

Also, your CYA is low for a SWG. I think it should be 60-70.
 
AndyTN said:
This is above the water line so it wouldn't make any impact on your test results. Spray some bleach into your coping cracks to see if it kills it. I get dirt accumulating in my coping cracks too.

Also, your CYA is low for a SWG. I think it should be 60-70.
Click to expand...
Yeah, the water and the fiberglass all look good, no black stuff. But I will try your suggestion with the bleach and also work on getting that CYA up.

Thanks for the info!
 
Once or twice a year I get what we call a "scum line" in one or two corners of our FB pool. Kind of a seasonal thing I suppose since my chemistry is good. I don't have an autocover like you do though, so I can easily wipe mine off with a Magic Eraser. In your case, the bleach and brush are probably best as suggested. Andy is correct about the CYA as well. Increase it to 70 which should help your FC hold better. It's on the low end for summer so be careful. Have a great weekend. :swim:
 
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