What is this

[cgthebeast]

Not the best pic because i only can use my ipo camera, but it's like a moss that browinsh gray, brushes off easily.
I use rodi water, water change every other week, stock is only a fire fish. Parms and everything test out great and my salt level test out around 1.023. Set up for 7 months
Also I have this brown slime like substance on my sand ,it isn't ditioms, they never go. I've tried blackouts and such but it still dosen't work

 

[mr_X]

Maybe cyanobacteria on the sand bed. It comes in colors other than red.
How is your flow in the tank? If that stuff easily comes off your rock I would think an increase in flow would be a big help. Do you vacuum the stuff off of the rock with each water change?

 

[cgthebeast]

I agree, I think I might have a ditom look alike case of cyano, I'm planning on adding two more power heads to see if that works hopefully. I actually scrub my rocks with a toothbrush to try to get rid of it, but it jut comes right back.