OK... I just got home. The water is crystal clear, but there is this "debris" on the steps and bottom of the pool that collects wherever there is a contour change, corners, etc.
This is definitely not sand, at least not the kind of sand that I've ever seen before! When I brush it it turns into a cloud that dissolves within seconds and is gone! Whatever it is, it is incredibly fine, like a rust-colored dust...
Gonna do the OCLT again tonight, but I'm sure it will pass. I'm also sure that when I get up in the morning the dust will be back :-(
I've read some other threads here where guys were talking about a unique kind of algae, but wouldn't the chlorine kill that, and wouldn't there be CC in the pool if that was the case?
Any help with this is greatly appreciated... i will try to get pictures of the "dust" tomorrow and post...