Our sidewalks have started to get round black spots in various places. They are dime to quarter size in diameter. In some shady areas they are so dense they almost merge together. So far I have sprayed with 50% diluted bleach, and I tried a test area with some blue miracle liquid I got at Costco. The concrete gets lighter but the black spots remain.

Is there fungus among us? Has anyone successfully dealt with this?

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1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma

Power wash it.

Will prob grow back but is much easier to remove the second time.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)