Pleas help ID algae in new tank

[Subarody]

New tank with dry rock/sand. Cycle finished around mid October 2020. 2 Clownfish added to display November 26, 2020. Cleanup crew and 2 zooanthid frags added beginning of JanuaryAlgae has taken off in the last week from first appearance. No previous algae outbreaks prior to this.

attached are tank photo and microscope photos. There is green algae hue covering the rocks and then this brown looking film overtop of that and on the sand. Brown strings hanging onto sand flowing in the current

Salinity 1.026
Nitrate 2 ppm
Phosphate 0.1 ppm
Ammonia 0ppm
Nitrite 0ppm

Any help would be appreciated.

 

[Subarody]

Here is a video as well...

 

[Subarody]

I’m concerned about Dino’s but not sure what to look for. I thought there were some obvious diatoms when looking at the microscope (no photos of those ones) but I can’t say whether the photos above are dinos or just some other algae/bacteria. The brown on the sand looks a little worse (darker and more strands flowing) at the end of day but not significant. Not sure if I should vacuum the sand or do any big water changes or just let the natural profession take place. Last water change was almost 2 weeks ago ( I typically do 30% every 2 weeks) and it’s time for another one based on my schedule but the parameters don’t seem to need it and I don’t want to strip the phosphates and nitrates if this is Dino’s.

any thoughts?

 

[Spare time]

Green cyano maybe? It would make sense given no nitrates but decent phosphate.