Well another colony is gone. Pulled these stars off it. I have lots of asterina stars but these guys are bigger and black. Must have been around 8 on the Colony. I dipped the skeleton hoping to get a clue but it's still too cloudy to see thru the container. My paramiters are solid and it's an older tank full of nice live rock and plenty of corals but every week I loose a colony or frag. They seldom are close to one another either. A hope and a prayer that something pops up as causing it. I am doing 25 to 50% water changes every other week and running carbon and resin ( cuprisorb) for metals. Good lighting and flow. I have checked everything several times but can not figure it out.