After i posted last night i remembered what i used to do to stop RTN when i was too lazy to frag something or it was already too small. I discovered it years ago when i chucked a new small colony in the sump that was really blowing up with RTN from the bottom up the night i bought it. It was only $20 because the store knew it was in a bad pale way. Anyway the move to my tank was the final straw and within hours it began to get 'that' look and a few hours later after lights out i saw the flesh peeling away. After it reached up halfway in about 30 mins i grabbed it out and literally dropped it into the sump/frag section with the sh*ts over losing it. It was going so fast i didn't think it was even worth fragging.
The next morning i turned the lights on and the colony is upside down where it landed on the 1" deep sand bed. Completely white as expected. I pulled it out to throw it and all the branch ends that were buried in the sand were still covered in tissue. I placed it back in the display the right way up and 24 hours later there were about 50% more dead tips but the rest recovered and i fragged the you know what out of it to make a new mini colony with all the good bits and a tube of super glue.
So last night i took the branch and completely buried it in the sand in the sump, it had gone a bit further than in the video but it also lost about 10% more tissue after being buried. Tonight i took it from the sand grave and low and behold it still has tissue. Within about 2 hours i could see a tiny amount of PE on some of the tips so i'll be surprised if it starts RTN'ing again. There will probably be some more slow die off on some branches but a good portion of it will recover in most cases. If you think 'why not just frag it instead of burying it' - because with this way if you catch it soon enough you can preserve the integrity on an entire piece or colony without destroying all of the growth it's taken you years to see. Also works on small frags - yes i have experimented just as i always do - you know me lol.
It really does work but you can still see the tissue loss restart and lose everything just as can happen to last ditch frags, don't just sit and watch an acro implode - frag it or bury the bloody thing.
Here it is tonight. I only had the B+ lights on as it was bed time so i used the phone flash to light the shot. The yellow tang looks better than my acros at the moment which sh*ts me right up the wall tbh............