What is this stuff?

[Zhaug31]

From what I’ve read I’m assuming it diatoms but I’m brand new to this and not 100% sure. It’s everywhere in my tank. All over the return, sump, rocks but not so much sand. I had some Cyanobacteria show up for 1 singular day then it disappeared. All I have in the tank at the moment is stowaway fiddler crabs from the rocks. I’ve just set up my reef tank with natural sea water and rocks and sand from the beach. I added fritz turbo900 2 weeks ago.

 

[vetteguy53081]

It’s what is called mulm
Take a turkey baster and blow loose and net the suspended particles or a cloth rag and wipe off
It is very similar to detritus

 

[Mr. Mojo Rising]

If it can settle and build up like that, its an indication that you need more Flow