What is this on my sand (pic)?

[Mikro]

Is this possibly diatoms?

Here is another

 

[SFlogic]

cyano?

 

[avshockey311]

I would also say the start of cyano.

 

[Mikro]

The weird thing is its only on the sand and not the live rock...

 

[avshockey311]

When I have cyano outbreaks that is where I usually get it too. I hardly ever see it on my rocks. I get it in the frot corner of the tank in my sand. I cant figure that out because that is some of the highest flow in the tank.

 

[MAreefer1]

cyano isnt a good thing Its dreaded by all reefers