How to identify diatoms vs "other"

[PedroYoung]

I think I've got some diatom explosion going on in an established tank. Is there a way using microscope or other to identify positively? Powdery sort of brown coating on all surfaces, not cynano-like.

 

[sixty_reefer]

Do you know your silica?
mother things to look is po4 and no3 is any of them at zero or near?

 

[PedroYoung]

Do you know your silica?
mother things to look is po4 and no3 is any of them at zero or near?

Yeah, silica is usually around 125 ug/l on Tritons. Randy on the chem forum says that's cool. PO4 is usually around 0.03. I'm trying to lock down what's actually in there (algae vs diatoms) before I go chasing rabbits.

 

[sixty_reefer]

Yeah, silica is usually around 125 ug/l on Tritons. Randy on the chem forum says that's cool. PO4 is usually around 0.03. I'm trying to lock down what's actually in there (algae vs diatoms) before I go chasing rabbits.

Have you got any pictures

 

[PedroYoung]

Have you got any pictures

Here are some phone pics with filter. I actually ran a test from the “are you sick of dinos yet” thread which instructed to put a sample of the material with 100 ml of tank water and 5 ml of H2O2. There were bubbles generated which is supposed to indicate not Dinos or diatoms, but instead cyano. I’ve never had brown cyano, but maybe.

 

[sixty_reefer]

It does have the look of Lyngbya. Does it grow in the shade?

 

[PedroYoung]

It does have the look of Lyngbya. Does it grow in the shade?

It does not seem to grow in shade. I looked up Lyngbya. It seems to be stringy? My pest is really more like a powder, will toothbrush right off and doesn't really get vertical from the surface.