I've used purple up in the past. Honestly, as long as you keep your parameters as consistent reef levels, coralline should naturally grow. I have found when using purple up that I got a rich purple algae and upon ceasing it the algae maintained a lighter pink hue. I don't know that the product really "accelerates growth" or promotes growth in unstable conditions, but it may provide elements that allow for rich colored coralline. Just be careful what you wish for. Coralline is pretty and an indicator of a stable tank, but when it's growing all over your glass, pumps, etc - it can also be a pain to deal with. Unlike other algaes, coralline is tough to get off and you can damage even glass tanks and equipment trying to remove it. My recommendation would be to let coralline occur naturally, offering you time to control it as you see fit.
