i have pics of my tank absolutely wrecked by red mushrooms, and then zero within 2 days not trying to fill up your thread w pico reef pics but can pm them if you like.
the scraping works, true I left tissue on a few spots but its not rampant takeover, simple lift out and gouge out the area one last time with a pair of wirecutters or even a dull knife as a slice rip. Your rock is easily lifted from the tank, doesn't have stacks on it so access was 99% of my issue, I had it all crammed in a small container and couldn't get to them all without full takedown which did occur.
Your coverage is so large though, I actually wouldn't take time to scrape it all off I would vinegar burn it off. it takes a while to dissolve rock that thick and the mushrooms will begin to release after a while and float off or be really easily peeled off and it leaves almost no tissue, again 10% retouches on something that set in aren't a surprise.
would simply have the rock on a table and use a mister pump to spray good vinegar right on the shrooms and occasionally the nontreated parts of the rock with clean saltwater pours, this all can be done without recycling the rock. it may take two hours being out on the cabinet basting but they'll begin to release and be easily removed as the top 1/16th of the substrate hold also begins to turn loose. id be re applying the vinegar over and over, several creative ways to apply beyond this as well without affecting the non target areas
vinegar is among the more biologically tolerable options for living dissolve, of course the acidity clears the local area but we dose this stuff in our tanks directly, diluted, the non treated parts of the rock wont be affected and keeping them wet w saltwater keeps the bacteria alive even if you did it for two days.
id have those rocks cleared in one weeked w vinegar mist
then use the scrape to catch the leftovers, ridded in a week.
