Urgent Is this Aiptasia!?

I always loved the grape caulerpa too. When my last tank crashed 6 years ago, I couldn't figure out what happened & never had anything to answer for the overnight death of everything I had. Never started it back up, either. Now, years later reading a whole bunch of stuff, it was the caulerpa when it released all the toxins back into the tank. I even got a pic of it "losing its green" cuz I thought it someone might know what was going on with it (I was worried about the darn algae LOL) and posted it on several forums, and no one said a thing. Live & learn!