Diatoms or Dino?

I'm fairly sure it's diatoms because there are very few bubbles, but it's persistent and annoying, so a second or more opinion is appreciated. I don't mean the GHA... Just the brown stuff growing on it as the GHA dies back.

http://i779.photobucket.com/albums/...7-8515-4ACB-BB40-54C39D1D901B_zpsdqtv2yzx.jpg

Sorry, they improved Photo bucket and now I'm not sure how to embed the pic correctly.

Got it!

 

Diatom blooms occur in the presence of elevated silicate levels. Have you added new equipment, rock or substrate? I have never seen furry diatoms but I have seen brown cyanobacteria.

 

I have not added anything new recently. Note, it isn't very clear from the picture, but the brown film is living mainly on dying green hair algae. That is what makes it look furry. My concern however is the brown layer growing on it. It has been persistent for months. As the GHA dies, the brown seems to get worse.

My concern is that when I turn off the pumps, the stringy filaments become little clouds of brown. My snails seem listless. I aggressively stripped silicates for a few weeks with little effect. On the other hand, no bubbles to speak of.

 

I guess the next alternatives might be a complete black out and or trying some products with GFO if you have not.
Remove as much manually as you can. Have you measured phosphates?

 

Phosphates at 0. My nutrient issues have, I believe, been solved as evidenced by the ongoing reduction in hair algae.

My biggest concern with a blackout is my maxima clam. I don't want to move it and a potential infestation to another tank, but I'm not sure how long it will survive without light. Any ideas?