Have absolutley no algae of any kind anywhere else in the tank alk spike was 7.8 to 10 with a large waterchange. No new frags added lately.
I used revive to dip. And tissue loss is on tips as well as up one branch.
2.2 dkH in one water change is definitely big enough to cause alk burn and necrosis. As far as algae growing on dead tissue, I have only seen algae that was elsewhere in the tank populate on the dead tissue, not appear out of nowhere. However since you are ulns, the necrosis could be the only source of nutrients allowing algae growth i suppose. I have also had cyano in a ulns system and that could have just started there.
There are 3 things I would do:
1. First try manual removal of the algae (if possible) and see if it reappears and if so how quickly.
2. If you can collect a substantial amount of the algae (let's say a dime size minimum in this case), then you can perform a test to help determine if it is dinoflagellates or cyano.
Put the algae in a water bottle with tank water. Shake it up vigorously for a minute and then strain it through a paper towel into a bowl or glass.
If it any "magically" reforms within the bowl 45 mins - 1hr later, it's likely a type of dinoflagellates. Most cyano will stay in the paper towel and although it can get through and reform, it will usually take much longer and not regroup to the same extent.
3. Try dipping affected acros in bayer while blowing with a turkey baster or powerhead (please research how to properly use and rinse after bayer to avoid any personal health risks/issue with your tank), as I am not sure revive would be sufficient in killing or even stunning aefw or red bugs. I have never used it however.
My guess at this point is that it is simply run of the mill diatom/algae/cyano growing on dying or dead tissue caused by alk burn or stn.
