Stewart, it definitely looks like rust but Some areas have a full leaf imprint. 
The area that looks like efflorescence turns to a brown stain when dry. That's why I took a wet & dry pic of it. A pile of leaves sat in the corner of that step in a puddle of water for days then poured over causing the stain.
I'm going to try some Klenzstone & Rust remover.

Tony DeLuna
925-625-9625
www.PatriotStoneRestoration.com

On Oct 20, 2016, at 11:33 AM, stuart rosen <mail@stoneshine.com> wrote:

Tony,
The white stuff is efflorescence -I dont see any leaf stains although the brown could be. It looks like to rust to me.
I think you should hold off on sealing. While sealers breathe it may slow down the transmission of vapor.
There could be more efflorescence and the installer will blame you-I would hold off servicing that stone until the install was completed and it rains a few more times.
Let the Mason deal with it-I would put on my running shoes and run to a nice predictable interior marble job.

On Thu, Oct 20, 2016 at 12:12 PM, Tony Deluna <tndeluna@gmail.com> wrote:
Hey Pro's
Does any one know how to   Clean off these stains with out having to use a poultice? It's an exterior patio with many oak trees & others surrounding. They are not even finished with the installation.
The rain came and leaves fell leaving stains.
I tried cleaning one step with the runs on the side. No difference.
When it's dry the stains have a brown tint, when it's wet The stains are lighter like sealer with spilled running down the side.
We are planning on sealing it with 511 porous plus.
What are your thoughts?


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Tony DeLuna
925-625-9625
www.PatriotStoneRestoration.com



--
Regards,
Stu Rosen
201-446-1200

"EVERYTHING MATTERS"


 
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