Sarah, thanks for the reply.
The one time I ran the NO3 test a few weeks ago, it was zero. There has been a problem with the C. Proliferata's leaves becoming translucent then disentegrating.
Maybe I should add a few fish. All that is there now is a serpent star, a few montipora, one or two small hitchhiker crabs, and innumerable worms and bugs, and feeding these guys heavily has not given me the thick 'carpet' of caulerpa I have seen in lagoonal areas. I seem to get more runners than I do leaves.