I have a similar situation, only with "some" of my corals, and oddly enough, it's the "easy" ones. I have great results with everything I've put in the tank, but can't get my GSP or mushrooms to grow to save my life (mushrooms are EXACTLY the same size as they were 2 years ago). Zoas are great. Polyps are great. Euphalia is great (a few different types). Even have a brain coral growing. Have some sort of unidentiified anemone that I got with the tank 2 years ago that I cant get to stop growing. But can't get the "weeds" to do anything. And I'm weird in that I "like" GSP... Guess that's why it won't grow for me.