Rust color growth on rocks

[Vuuduu]

Hey guys, so i'm starting a new tank going, been doing the cycle for about a month now. Ammonia is gone, nitrite still showing up at about 1.5-2.0 ppm (last week it was over 5.o, which is all my test kit went to), and nitrates are really high at around 80 ppm.

lights are going now, and my rocks are getting covered with brownish/rusty colored growth. Is this the diatoms I hear so much about, and should i just let it be? or should i scrub as much as i can off during my next water change?

 

[Vuuduu]

Here’s what it looks like

 

[Fudsey]

Looks like diatoms to me

 

[tdileo]

Diatoms.