I'm not sure if you watched one of the newer BRS videos on cycling and stability, but they mentioned that it really takes two years for a tank to fully mature and get into that "stable" spot. From my own experience with my 75G that i started with a bunch of reef saver rock, it really took it a year to start growing coraline algae. It's at three years now and this thing has seen every possible pest algae. It started with diatoms, then went to cyano and hair algae. I finally beat the hair algae using fluconazole or whatever it is, within the last 4 months. I'm still battling P04 problems but i have no hair algae in the tank. It just takes it awhile. Now if i turn over a piece of rock that has no coraline on that area, it takes it a month to get covered. Just hang in there, let the tank do it's thing. Id wait to add anymore SPS until at least half the rock is covered with coraline.