What's this stuff?!?

They seems like hair algae?

that is Brown Algae (diatoms) and this is likely to occur in new setup. it will go away once tank is established.

I've never seen fluffy diatoms before...

okapizebra said:

I've never seen fluffy diatoms before...

Click to expand...

So the algae knowledge bases are not catching up...

http://www.plantedtank.net/forums/showthread.php?t=84947
http://www.plantedtank.net/forums/showthread.php?t=143401

It's not a new tank, has been set up for months. To me it's almost like debris, like my flow is too slow...

Read those threads, I wonder if I have a tad to much light? I have two cfl 15 with a foil reflector in this hood, it's a ten gallon, I'll remove the foil and get rid off all the duck weed thats got.

what kind of substrate is it?

Mgocps with a pool filter sand cap.