Orange bacteria or algae on media bags?

[W00F]

Hi everyone,

I have 20 gallon AIO with a media caddy.
The media bags of carbon and GFO started growing this orange substance.
I replaced the media and it grew again.
Does anyone know what it is or have a guess?

 

[Rp8]

A better pic would help

 

[W00F]

I have these two pictures too. I’m trying to get closer but haven’t connected my camera to my scope yet.

 

[Cole.mormon]

Looks like breakdown?

 

[Cole.mormon]

Algea maybe

 

[W00F]

Looks like breakdown?

It’s not really old (couple weeks) and on both GFO and carbon.
Haven’t seen it before and have had it in there much longer in the past.

 

[W00F]

Algea maybe

think it’s a concern?

 

[Cole.mormon]

Possibly

 

[taricha]

That orange color to me suggests it's related to the GFO (Iron-related).
Iron bacteria grow that color, but I don't know if I would consider that an issue to be concerned about.