Thats where you alk and calcium is going. The more you dose the more it's going to grow. Welcome to the pia if coraline.Yes, coraline is growing a lot. Anything new gets coated within a few weeks, and it is hard to keep the glass clean.
I suggest a rock boring urchin. They love coraline. I haven't see it pick anything up and carry it off. I have loose frag plugs and shells. Never carried one off.