Part 1 of B-ionic worked very well. I used it just as I use it in my tank, not the concentrate. I'm surprised by how well it worked. I'm definitly not going to kill it throughout my tank, I'm just going to limit the spreading. The toothbrush is a really good idea as well. I might have to try that. Well now we all know what to use if you want to control the spreading of a coral, although I don't think many will want to stop a coral from growing. It also worked on a small piece of milleapora which was not intended but it was nearly touching the cap. I am trying to control so I'm sure it would work on SPS but I don't see those spreading quite like this.