Can't help with the bryopsis, but I can give you some advice with flatworm exit. I have a feeling that if you have a deep sand bed, you need to re stock it heavily after using this stuff. That might have been one mistake I made when my acros crashed; the lack of sand bed life led to a build up of nutrients which the SPS could not tolerate. Now that I've restocked my sand bed heavily, including 50 bristleworms and several pounds of "invert sand" from inland, my tank is beginning to come back to health; the few SPS frags I have left are doing much better.

Good luck, Mike!