Best product for cleaning green algea-looking stuff off siding?

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Flyover

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Can anyone recommend the best product for removing a bit of green algae-looking stuff off the side of my house? It's vinyl siding.

I was just going to scrub it with diluted bleach or multipurpose cleaner but I figure there's probably something better suited to the purpose.
 

oldognewtrick

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Scrub brush on a long pole like a broom handle. Spray the area with Simple Green or Purple Power.
 

Sparky617

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Speedbump

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If it's algae, bleach water works amazingly well.
 

oldognewtrick

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DO NOT EVER use a pressure washer on any asphalt or wood shake roof system unless you want to rapidly reduce the life span of the system.
 

nealtw

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A friend had white vinyl siding, one of the kids spilled a grape soda out the upstairs window leaving a nice purple stain that he cleaned with soap and water. when it dried he now had a white strip down the house.
He tried several things to clean the rest of the house, nothing worked until his neighbor suggested citric acid and that worked but I don't know what mix he used.
 

DFBonnett

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I used "Spray & Forget" that I got from HD for moss on the roof. Non-toxic. Took a while to work, but worked well. If and when I have to repeat, I will use this product again.
 

joecaption

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If I did not have a pressure washer Wet and forget is what I would use.
 

Sparky617

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What if the pressure washer doesn't help?
For siding I'd spray it down with a mixture of bleach, hot water, and a bit of dish detergent in a garden sprayer. About 1 cup per gallon of water and a tablespoon of dish soap. The dish soap acts as a surfactant and allows the bleach water to work. Then hit it with a pressure washer after it sits for a few minutes. Wet and Forget will work, it just won't be as fast as the pressure washer method, especially if the siding is really soiled.
 
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