Hi all,
It's my first post so be gentle.

I recently installed some WRC screening during a backyard reno and have been having trouble with excessive black staining running down the face. Refer to the pics.



I used Organoil decking and exterior oil for the first time on this job after the intergrain products changed their formula. It was bad enough that the deck looked yellow.

I cleaned it off once and left it for a few weeks to weather and see what would happen. What happened is the phone rang again and now the clients are not happy again.

Can anyone tell me how to fix this? I've never had this problem before.