What's wrong with my setosa?

[mrhasan]

Hello SPS gurus. I noticed that my setosa is developing some white fuzzy stuffs on the tip of two/three branches at the back. Its not bleaching since those were in shade and the upper part is doing well. It has some kind of fuzzy slimy stuff on it:





The coloration have gone much better since I got it along with new growth. I thought that it might not be getting enough flow at the back so I have changed the location to a higher flow and higher light area.

Any idea?