Need help with dinos and dying corals

[Mata_01]

So I have a 20 gal aquarium that has been running for almost a year, and since July Dino’s have appeared, first i thought it was cyano but now with some tests I know it’s Dino’s, I have been running a UV light.
I first try to remove it from the normal ways, increase nitrates, blackouts etc.., then I tried live copepods, and they have done an amazing work because they almost killed them but now they just don’t disappear, I have been cleaning them day yes day no, and no water changers were done, I just don’t know what to do. And I have been adding bacteria too.
These are the parameters:
-Alk - 9.9
-phospates - 0.04
-Nitrates 50 or more
-salinity 1.026
There is some Dino’s in the glass because I still didn’t clean it

 

[Uncle99]

Seems duplicated

 

[Mata_01]

Ye the first one didn’t have the photos