Coralline will spread as it sees fit. I've seen tanks get covered, if not overwhelmed, by the stuff in a couple months. Mine doesn't see much spread of it at all, where there are a handful of 'spots' growing here and there in my tank after years.
PurpleUp is a money sink that doesn't do anything. Alk
and calcium in a bottle...you already put that in with your salt mix and water changes! Keep things nice and stable and it'll grow...as for how fast that is up to it and your tank. Personally, it sure looks nice but I like my tank not being overwhelmed by it and having to clean it off my powerheads monthly. Sometimes even the good stuff can be a weed.