Mustard Algae?

[Markgkda]

Customer wants his vinyl siding cleaned. I have cleaned many vinyl houses and removed green mold mildew algae etc but this stuff appears to possibly be mustard algae? It is very yellow. I applied 25% water 75% 12% and did get some of the surface heavy off but even with several application letting dwell and scrubbing even still has considerable staining. Questions are: what causes this type of algae vs the green stuff and is it possible that it has stained the siding so severely that it will have some permanent staining? Its been on there for a few years so the customer says.

 

[HighTide]

Mix up a little oxalic acid and spray on and see it that works.

 

[Rapid HotClean]

Thinking out loud, looks like rust?

 

[Doug Rucker]

Yeah. Looks like rust


Doug Rucker
Clean and Green Solutions
Pressure Washing Roof Cleaning School
Call or Text 281.883.8470

 

[Craig]

Looks like rust to me, too. If you have F9 BARC, go 2 or 3:1

 

[Greg Rentschler]

I 4th the rust oxalic and a brush and I bet it comes off.

 

[Craig]

How'd this go, Mark?

 

[Rance]

Yeah, what Craig said. Inquiring minds want to know!

 

[Paul Kassander]

I also concur it may be rust or staining from the soil. either way some F9 should take it right out.