Boarder wars? The favia had not been aggressive toward the cyhphastrea until now, but that sounds like a logical conclusion. I'll keep the algae under control and see what happens. I recently had my scoly go into recession too so I'm watching it. Yes, Mag, CA, Alk, SG are all fine and no phosphates thanks to GFO reactor. I did dip the scoly in revive to preclude infection as one possible issue.
Thanks for the input!