You have said yourself - that you cant keep certain acorapora- right?
MN that used to be the case before I upgraded my lights from the water cooled ones I built to real lights that are bright enough. I now have quite a few acropora, maybe 5 or 6 that have grown from fingernail size to 6 or 7" since I moved here two years ago.
I also use 100% NSW now because I live near the sea.