So I have a similar looking algae, that has been around for about 6 months, and getting worse.
I tried flux rx. I used the full 7000 mg, since I have a 300 gallon tank, with a 40 gallon sump (close to 350g). I followed the instructions (removed carbon, turned off skimmer for 72 hours, etc). Some of it turned white (not all), but it all came back within a few weeks, and it is as healthy as ever now. I did however put the carbon back in and did some water changes at 72 hours. I am thinking this may be why it didn't die.... Should I try it again? And if so, if it doesn't die after one dose (10-14 days), should I do it again?
I have been spot treating with h202, and it seems to be working, but is very time consuming. I have not seen any adverse effects with the corals, but it may have killed my shrimp. I think it will take me years to get it under control with h202.