No it is everywhere in the tank. I think it is Chrysophytes "golden algae" it looks and sounds the same. Cannot find much information about it other than it is usually excess silicates and po4 also vibrant seems to work. Picked up vibrant today and a uv sterilizer hoping for success
regarding "excess silicates", it happens every time my rodi system is overdue for maintenance....and I tend to only recognize it from the corresponding algae outbreaks.