mildew

[ghouchu]

anybody know of a non-bleach product that will kill mildew? a deck i recently washed had some seriously tough mildew. in places, i was able to kill it with bleach only by using highly concentrated bleach--and that made the wood lighter in that area, requiring me to redo the deck with the highly concentrated bleach--and i still didn't get all the mildew. we're basically talking pure clorox with some dawn and liquid tide thrown in, 5 minutes dwell time, and there was still some mildew. i had earlier given the deck 2 soapings--same mix applied with pressure washer--with 15 to 20 minutes dwell time each time. suggestions?

also, bleaches say to avoid contact with metal. what should i use on the metal gutters of a house to kill heavy mildew?

thanks

richard