Rust-colored patches growing on rocks

[clown99]

My tank is 8-month old biocube 29G. In the past 3 weeks I notice these rust-colored patches spreading on the rocks. Please help identify them and course of actions. Thanks in advance.
My parameters:
Lighting is DIY LEDs with Bluefish mini controller.
6 Neutral White LEDs, 35% at midday
6 Royal Blue LEDs, 65% at midday
6 Blue LEDs, 65% at midday
This is the lighting profile:

This is tank parameters taken on 06/28/19. Alkalinity is measured using Hannah (H) and Salifert (S). Salinity: 1.026, temp: 77.8, pH: 8.15.

Tank overall, lots of CUC, cleaner shrimp and pink-striped goby is hidden.

Rust-color patch #1:

Rust-colored patch #2:

 

[EmdeReef]

Diatoms or dinos. What’s the texture of the growth like? Slimey or powdery? Try to blow it with a turkey badger, usually diatoms will disperse like dust.

 

[clown99]

I'm not able to blow it away with a turkey baster. I took out the rocks and scrubbed it with a toothbrush. It's somewhat slimy. It is coating the rocks.

 

[Bryson.bobby]

Looks more like a cyano than Dino