Hydro-Pro Power Wash

I remember as a kid a that my dad used to bring home retired work motivational posters, and one read "Measure twice, Cut once." My new maxim, when it comes to roof cleaning is, "Inspect twice, set your ladder ONCE." Thanx for all the help on this guys. Have a great summer.

So it's like shampooing, "Lather, wait, repeat (if necessary)."

Thanx for the help guys. I use the 2:3 ratio. How much time is normal between applications? Minutes, Hours, Days? Thanx also for the encouragement. I'm not alone.

I recently had the experience where I sprayed a roof with the "quick apple sauce" and the algae changed from dark to yellowish. Am I expecting too much too soon? I'm still very new at this no-pressure roof cleaning, and get hinky when a roof doesn't look clean when I leave a site. Please help. Thanx.

What affect, if any does the copper sulfate have on the asphalt roofs? I considered buying some, but the warnings gave me pause until I can get some more answers from you gentlemen.

If what I am dealing with is rust, could Whink Rust Remover be a better option? Is the hydrofluoric acid safe to use upon a roof? I am familiar with oxalic, but haven't been impressed with it upon tough rust stains.

Hello Folks, This is my first official post as a member of RCIA. Be nice now! Any way, I got a call from a customer today, and she is telling me that the stain on her two year old roof is from her oil burning furnace (NH). Can anyone confirm this hypothesis as being possible? Is there a prescribed method for cleaning such a stain? Thanx in advance. Mark A. Dadian Hydro-Pro Power Wash, LLC Laconia, NH