Glad to hear all is going well. How large is the new piece of live rock? The live rock you added might be pushing your tank into another mini-cycle, depends on how long it was cycled for. I've noticed in my little tanks that it does not take much in terms of adding new live rock to upset the balance. . . and my tank is a 20g.
As far as the zoa's spreading, give them some time, and its pretty likely you'll have more on that new rock too. I had zoa's in my nano and under T5s, they took over pretty quickly, hope the same happens for you!
As far as the zoa's spreading, give them some time, and its pretty likely you'll have more on that new rock too. I had zoa's in my nano and under T5s, they took over pretty quickly, hope the same happens for you!