Coralline not growing

[Jaws]

Lately I've been having a problem getting the coralline to grow on my live rock. It's growing on the back wall, not everywhere yet, but the rock that I've had in the tank for a year is not growing anything more than what was there a year ago. I've added a bunch of really nice pieces completely encrusted in live rock to help speed the process up a bit and all that's done is manage to make the coralline on the new rock look sick and start to fade. Any ideas?

My Calcium is always above 400 and I've used everything from Kent part B solution to aragamilk to Kent liquid reactor.