Never heard of phosphate, let alone a 0.23 reading, kill a coral like that before. I think something toxic was introduced to the water. That is my best guess. The tendency to point to things we can test is common but we can't pretend we have controlled enough variables in our tanks for that to work all the time.
I don’t think it was the .23 phosphate reading that killed things. It’s my best guess that jumping from .13 to .23 overnight caused many LPS and SPS in my tank die. That was months ago and I’m still battling LPS death. So that’s why I started reading into cipro treatment to possibly kill whatever is killing corals. The thing is I have lots of beautiful fish and I’d hate to harm them in the process. That’s why I’m still searching for answers.
If they are dying to brown jelly the best way to save them is to frag the healthy branches and dip those in some lugol's solution. Discard the infected pieces. If you can't do that then give the whole colony a dip in lugol's and hope for the best. Keep it fed if it eats and don't give it full light.
I tried a peroxide dip and I have a seachem iodine dip on hand but both didn’t work. I also tried pruning off BJD branches but they all ultimately died. I only have some blastos left at this point as far as LPS goes. I did lower my lighting as well. Gonna try to rent a PAR meter over the next few weeks and shoot for 100 on the sandbed numbers.
