I read the same info on their website. They also pre-emptively strike down the ARMA bulletin and say that its outdated. I will not honor them by providing their link, but heres is a piece of their "Roof Cleaning Science" page. (pffff...Science?)
If you research roof cleaning on the Internet, you will encounter claims, counter-claims, arguments and outright confusing and conflicting information among the different roof cleaning camps. There are those who make the argument that ARMA, [FONT=verdana,geneva]in its 2007 Technical Bulletin[/FONT][FONT=verdana,geneva] recommends the use of bleach to attempt to tackle the roof algae problem. The bulletin does not however, comment on the impact of bleach on your landscaping, or its toxic fumes, or that it voids many termite treatment warranties. In addition, the bulletin states quite specifically when referring to roof cleaning with bleach that "The effectiveness of such cleaning techniques are only temporary, and discoloration will likely recur." [/FONT]
[FONT=verdana,geneva]An important point to make here is that many improvements have been made in the roof cleaning industry since that 2007 Bulletin was published, including the introduction of the eco-friendly Roof Shampoo® roof cleaning process which debuted in 2008.[/FONT]
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