Dino or diatoms in new tank

[eriqq1]

hello everyone,

would you be able to identify brown algea on the pic? it started like 5 days back and slowly spreading. this 17 gallon tank is 2 - 3 weeks old(adding nite out II and blend bacteria) so diatoms would make sense nevertheless have the feeling it dissappears dramatically overnight and reappear during photo period which would point more towards dinos?

i do have no3 at 20ppm and phosphates below 0.02 (no absorbent, HOB filter with matrix and activated carbon, HOB skimmer, just feeding frozen food)

increased flow just now and thinking how to approach this (possibly peroxide if dinos IDed positively? I increase po4? syphone them out? )

 

[taricha]

diatoms would make sense nevertheless have the feeling it dissappears dramatically overnight and reappear during photo period which would point more towards dinos?

we might notice it more with dinos but a "diurnal vertical migration" (up or down) is common in diatoms, dinos, and cyano.
It's early in the system. call it uglies, suck out any that is too brown for your liking and let the tank mature without worrying too much about it.

 

[eriqq1]

thanks! I I kept reading and eventually learned other algea can migrate as well - was not able to find edit button anywhere to update my post