Took out every single rock in a 220g... now this?

[LesPoissons]

Hey all,
Battling gha for months and months. Finally removed every single rock in my 220g, scrubbed and scrubbed and rinsed and rises and did a 100 gallon water change. Replaced in my tank yesterday. Now fine reddish/brown dusting/stringy hairs on the rocks. What is this? Dinos? What should I do now?
24 hrs after putting everything back:
Temp 77
Ph 8.2
Nitrates 1
Phos 0.03
Alk 9.4
Ca 471
Mag 1255
(I’ve now discontinued my ca and alk dosing since so many of my corals have died)

 

[NashobaTek]

Been there, done the rock scrubbing and I still have GHA, sooooo getting a skimmer because my phosphate is way high.

 

[Tonycass12]

Looks like dinos to me with all the air bubbles trapped in it. Are they disappearing at night? I have something similar but not this bad. You eliminated the competition for them and they bloomed