Is this diatoms or?

[125mph]

So I had cyano issue and used chemiclean, which looks to fix the problem. But after 4 weeks now, I still have brown stuff on my sand and it might be diatoms but not sure. What else can this be?

I did dose a lot of silicates last year to stop a Dino issue so maybe its diatoms feeding on silicates?

 

[Skippy The Meh]

Are there any micro bubbles on it or floating around the tank?

 

[Ben's Pico Reefing]

Stringy and mucusy is cuyano dusty is diatoms. Syphoning and cleaning sanded can help. Sand sifters like nassarius snails and conchs do great as well as any sandsifter. This appears to be diatoms based on what I can see.