Agreed on potential courses of action but you can model the outcome and not guess by acting on the whole tank. Most choices you can make will kill the target, it's growback that varies
To take any action on that tank and target without basing actions on a test rock is guessing even if the ID is pinpointed but most would rather just dose tank and see what happens
we can find compliant and non compliant examples for any invader online so it's not about id alone IMO it's about hedging vs guessing as reaction
Tank variables like clean/dirty sandbed matter...varying grazer balances and lighting balances among tanks. To know your variables you could do three or four test rocks to check for regrowth rates.
One you scrape it all off with a tool and treat with nothing, put back hand scraped.
Second is scraped with hard peroxide treatment done after scraping, externally, for the solid burn test. This usually complies the best but we can know.
Third is rock nothing removed, but soaked overnight in known peroxide safe dilutions, 1:10 for example (google that with peroxide/reef key terms it'll come up)
Fourth is test rock nothing scraped, but soaked couple days in a bucket with water spiked to 1900 magnesium via Kent. All the while the main tank endures nothing... you'll know in a week which is certain to be best.
I would take the verified best action not on a tank full of growth/mass, but on a tank you hand cleaned for a week before taking any action. The pre cleaning work is done so that the action taken now only has to prevent growback. Most will not do any of this, it's truly last resort but it is a sure fix as well. Dirty sandbed = fix for sure if applicable
