Basically what I meant Joe, whas that caulerpa can be growing just fine in favorable conditions and then something happens.
I will concede that there must be some sort of non favorable event to occur to initiate a spawning event.
But from my research it seems it can happen from anything as simple as a drop in nutrients, changes in salinity, temperature, lighting etc. Others claim it happens from time to time every so often with no clear explanation to them as to why.
So for beginner hobbyists It's just not the algae I recommend. Chaeto on the other hand I have no complaints with other than the occasional piece from time to time that might get trapped in a power head (typically no big deal). From time to time I may get a piece that makes it up to the display where it is quickly disposed of by my yellow tang.
It also has done a great job at keeping nitrates in my system at limited/non detectable levels. Which doesn't mean nitrates aren't in there. It just means they don't exist in excessive levels which is great.
I would actually like to ask the OP how high above the water line his/her lights are. I don't believe the cool white leds in the Eshopps refugium light fixture are ideal for algae growth. Or at least not the types of algae we are discussing. The problem with 6500k leds is that they are actually manufactured from Blue leds and lack any spectral output in the upper red wavelengths that are ideal for the type chlorophyll that we are targeting. 6500k compacts would actually work better as a fuge light than 6500k leds in this case unless you supplement with red. But they should be high range red. Not just any red led.
I think I need more coffee