It's razor. All of my tanks have caulerpa in them except my reef. It kind of goes hand in hand with seahorses, I think, and I've kept them for years. I've had macros that went south but not really releasing anything. I've had 3 or 4 total white out situations. Most of the time it just goes blaaaaaah.
It likes to be pruned.
It doesn't like to be over pruned.
It likes temp/salinity stability. Before I got chillers on my tanks, when there was a heat wave, I guarantee you there was caulerpa going sexual by that night.
Razor is more stable than any of it.
I keep the caulerpas, racemosa (Grape), cylindracea (another grape), taxifolia (feather), prolifera and serrulata (razor).
When ya wake up and find your grape looking like this.....
... this is the time to remove it.
If you go to bed a let it go through the night, you may wake up to this.....