Excellent! a true challenge.
You have more coral to worry about compared to that really bad red cyano thread where we can just burn it out
But that's the heart of the challenge, max results under constraints thanks for posting
Can you post a full tank shot, critical detail is found in them.
Also, was the bottle a new/unopened bottle of 3% peroxide from a pharmacy or grocery store, no where else? I say it like that because twice now the poster said it was a new bottle and after pages of analysis it turned out it might have been opened before, they didn't think it was really that important to have a new bottle.
We need to do two things along with your updated full tank shot
-not just broadcast dose the tank, take the amount you are using and spot inject it underwater right on the Dino strand test group of your choosing, with pumps turned off to maximize contact time
I found ways of maximizing the dose being used before upping the dosage, using a new bottle and changing the application approach to a submerged spot treatment test with pumps off for a few minutes.
Ideally, get a true medical syringe and needle for injecting if you can. Drug abusers have ruined our ability to get these for such legitimate science use...most places won't sell but some will.
There are new tools that are -great-for peroxide injection, thirty bucks, google
'Julian Sprungs thing coral feeder'
Direct contact time, even if briefly underwater with no current, massively boosts the effectiveness of an initial known safe dose you have already tried
If a new spot test shows quick rebound, or no effect, we have other choices and one involves upping the dosage or the percentage of peroxide.
The best way is to get a pic, spot test using this method until we see dieoff begin and then ironically stop dosing.
Don't keep pumping in the max safe dose we can see will elicit a reaction in the target; you stop dosing when an effect can be measured/seen and take time to manually clean/remove/siphon all the Dino out of your tank one last time
Now you know the preventative dose and you inject that amount now generally into the tank a few times to hit any regrowths in hiding, or if you see a new patch arise after this last thorough manual removal.
Based on full tank shot pics, that's what i'm about to recommend