You are 100% correct. Once infected it is not something that is easy to rid. It is not even a nutrient issue at all. These things are mutant. lolBryopsis is crazy stuff, very! I'm not going against anything that Brandon has said. He's very knowledgeable and very helpful. Only thing I want to state is that even with rock removal and multi h202 @ 3% attacks, bryopsis will come back one way or another. I've been battling this stuff for months on end. I have taken the same rock out of the tank 4x now, hit it with 3% h202 and left it on the rock for min of 15min before rinsing in a bucket of tank water and returning it to the dt. The bryopsis is starting to grow back on that same rock again, only 3 wks into the last treatment. I have hit 75% of my rocks a minimum of 2x and am getting grow back on ALL of them. This stuff has some serious holding power and imho is nothing like GHA, I'd take that any day in place of bry. as for what eats it, I had a nudi that basically acted as a lawnmower. It would graze the tops only which basically helps zero cause the stuff would not only regrow but keep spreading. Yellow tang and a 2 spot tang, multi types of snails and emerald crabs do nothing to this stuff. In tank treatments with peroxide is worthless on this stuff, been there done that. Out of the tank treatment or water removal to the point that the rock is out in the open is the only way. Down side is I believe at this point I'll have to hit it not only with peroxide but tech m. I know some say they've changed or you need to get the bottles with the contaminant in it as not every bottles the same. I will admit I'mat a lose. I have not tried the 35% h2o2 yet. Basically I wanted to give perspective to the op that just nutrient control will help get rid of this stuff cause it won't. My rocks almost look like they used to when I fist put them in, white with nice green bryopsis in the middle.