Dinos or something else?

[maxim.dockx]

I can't seem to define what kind of algae this is
Dinos?
Cyano?
Diatoms?

Tank is year and 5 months old
Reefer 170

 

[maxim.dockx]

Also

Params
25-50 nitrate (salifert)
Phosphate 0 (hanna) always had troubles getting it up though heavy feeding
Ca 415
Kh 8,15

 

[saltyfilmfolks]

Cyano I think.

 

[Tombones]

Looks like Dino "Amphidinium ".
I have them to.

 

[Randy Holmes-Farley Verified Community Expert]

That's why it's hard to know.

Looks like cyano to me, but I've never had dinos.

 

[Tombones]

I syphoned them from my sand bed and put them under a microscope. They swim. They have a tendency to disappear into the sand at night and congregate when lights are on. They appeared when I reduced the light cycle of my refugium to 13 hours so I moved the light cycle back to 16 hours. I hope the chaeto will out compete the dinos.