i don't think i see a brown film on it. where do you get lugos dip? i've been looking for it and am not sure which one to get. I was going to get it from amazon, but one reefer on here told me there was a specific brand.
I would remove all the algae around it and try placing it in another spot with different flow and light. If nothing works I would recommend a dip in hydrogen peroxide but be careful with this one as you can kill the Zoas as well