Please identify

[hardzip]

Can someone please tell me if this is diatoms or cyano. I am still learning here.
Any help is greatly appreciated
My tank is 5 months old.

My parameters are:
Calcium 431(trident reading)
All 9.2 (Trident reading)
Mag 1330 (Trident reading)
phosphate 0.02
Nitrate 10

Good flow 2× MP 40
Kessil AP9X
Waterbox marine X 110.4

 

[MaxTremors]

Looks like it, though it would be unusual in a 5 month tank. Are you using RODI?

 

[hardzip]

Looks like it, though it would be unusual in a 5 month tank. Are you using RODI?

yes I have a new spectrapure 90 5 stage.
TDS is 0