Dry rock is actually worse than live in this aspect, since pest algae gets in anyway and finds itself with no competition.
Vibrant, if it works, only works temporarily in many cases. As soon as more pest algae is introduced somehow, the same conditions that allowed the first outbreak will allow a second. Time for the tank to mature, and anything that helps it balance (biodiversity increasing measures like live rock and pods, appropriate cleanup crew, appropriate nutrient levels), are the two best things you can use on any pest algae.
You should be turkey basting any algae that grows on the frags off, so it doesn't smother the corals.