I would add a further direct access recommendation to any beginning dino invasion
be hand removing all colonies you can visually see, at all times, have none visual in the tank while that fantastic UV is running. UV is implicated in dino threads perhaps more than any other approach shown online. Nutrient adjustments are fine preventatives, don't rely on anything but a powerful directed siphon and daily work to keep the mass low, while you seek suppression or kill or competition, whatever your preventative method may be.
The lack of direct removal of the target when its very low phase like this thread is a huge problem in battling tank dinos. They're simply left there to grow in 97% of cases with water action methods being tried. perform the water experiments after the mass has been hand guided out, its your best hope.
a neat part of that reaction sequence is that ID doesn't matter in any tank battle if the first step is direct removal of a concerning target. If that's only a cyano mat making its nitrogen/etc then no harm no foul in having done a bit of manual gardening practice.