White spots on live rocks

[DanishDamn]

Hello All, its been 3 weeks i was running the salter cycle. Everything seems to be perfect until i added live roxk in reef tank. Over a night i see white spots on LR and LR started to turn black. I have no idea what's going on! If someone could help me understand whats this and whats wrong happening. I will be glad to find some information and rectify what went wrong.
Also inhave attached an image of that shitty rock. Its all over my LR . Please suggest me



Thanks
Danish