No worries, a little extra calcium won't hurt anything! It will probably help jump start things a bit! Corralline will spread to all of your rock in time (and your glass and powerheads, etc..) just keep your calcium in the 400-475 range and your alk in the 11-13 dkh range and you will have more corraline than you know what to do with. See the bottom pieces of rock on the left and right in my picture in the above post, they were completely bleached, dry base rock when I put them in that tank and now they have coralline. Once your tank starts to mature you will be amazed at what grows. I was cleaning my Fluval Canister filter today and i have about 30 tube worms attached inside growing on the inner walls of filter!