I always try not to look them straight in the eye. If I do they're sure to croak in a timely manner.
To be honest, sometimes they just go and you never figure it out. In this case tho, do you think there could be some chemical warfare between the softies/LPS and the SPS? Do you run carbon? Maybe change it out for new.
Other than that I'm fresh out of ideas. Sorry to hear you're losing stuff.
