Brown stuff inside media reactor with microscope, please ID

[Exus]

So I finally got a microscope, and want to get to the bottom of what this brown stuff is that appears after dosing lanthanum chloride. Appears after a day or two. It covers everything, tubing, sump, media reactors, skimmer, and rockwork. Is this a precipitate of lanthanum chloride, or is it something resulting from low phosphates.

 

[Dan_P]

So I finally got a microscope, and want to get to the bottom of what this brown stuff is that appears after dosing lanthanum chloride. Appears after a day or two. It covers everything, tubing, sump, media reactors, skimmer, and rockwork. Is this a precipitate of lanthanum chloride, or is it something resulting from low phosphates.

Definitely a very fine material, no recognizable shapes in the dark areas. i am guessing a chemical precipitate