White dust? on glass

[donf]

Three weeks ago I put 60lbs of LR from LR.com in my 46 bow. I have 2 PH, Remora Pro skimmer, Cascade canister (no media).
The past few days this white "dust" has formed all over the glass.
There is no livestock in the tank except hitchhikers.
Attached is the best pic I could get.
Please let me know what this is.

Thanks,
Don

 

[JPloman]

That is just an awful photo! Give me a better description and maybe I can help. To me it looks like air bubble on the glass, but I am really not sure.

 

[phishead]

I think its........... Chicago!

am i right?