Btw what made it come back was me adding about 400-500ml of H2O2 which was way too much as I found out
even corals changed colors, although none died due to it.
What I had for a while since dinos disappeared for the most part was a turf looking dark algae all over the rock. It did not really hurt anything, just made the rock look not super pretty and if you were to run a toothbrush on it clumps of "dust" would come up. Because of this I tried to dose some NoPox for few weeks, but didn't really see much change and the "new" smell from the skimmer was not working for me. So I stopped the NoPox. This after about a week or so cause few patches of cyano here and there. Being somewhat bored I decided to H2O2 the cyano, thus the large dose.
This did remove the cyano, but what came back was a blanket of dinos. So basically as of right now it looks like the turn algae is somewhat suffocated by dinos and nothing is really competing with them. Chaeto is growing in the sump, but not too fast. So I would say that eventually some other algae will step in and reduce the dino population again, however it seems like they will likely to remain there and wait for a new opportunity later on.
It is strange to me that my second tank never got this, even though I made no attempt to shield the systems. For water changes I would drain water from the 180 with dinos and put it in the other system, yet it never would grow anything. The only difference I see between them is that there seem to be a small clump of some unknown redish algae growing in the sump, but I doubt that it alone is responsible for keeping dinos at bay.