You have to try some steroids, hehe!!
Yes i know they have very powerfull rootstructure, so they can realy outgrow anything. I think that you only need a smal pice of the rihozome to start with, it will rapidly grov to a mature plant from that. I belive that you must keep them separatly from everyting else in its own refugium with som sand on the bottom. But if they like to be in the refugium they should pull out nutrients better then mangrove and as good as caulerpa.'
I have seen this plants for sale as plug plants in some nurseries in USA, but i cant get them here in Europe ( Sweden ).
Tommy