If it's on your rock it's going to consume it like crazy... I have the same issue in my DT after constantly trimming it back and maintaining it I finally gave up... Tearing down my tank... Drying the LR out and starting over again... Most likely your parameters are sky high in phosphates... But they say zero bc the calupera is consuming it. There's other people on here who can chime in on removal chemically by increasing alk I believe... But I'm not sure how to do it nor do I remember if it's alk or not. So don't take my word for it. Calupera is very intrusive when place in the DT... Sorry you're going through that... Hope you get some answers but for the meantime just manually remove what you can just make sure no spores get out otherwise it will spread like wild fire.
I am having an issue with my tank. I placed Caulerpa macroalgae in my display tank last year to lower my Nitrate and Phosphate levels. Now after a year of mostly perfect water parameters, my tank is over run with the macroalgae. I do not have a Refugium, so that's the reason why I did what I did. 
It's covering my corals. HEEEEELLLLLPPPP!!!
