I have a 75g reef. It has been set up since early last summer. I have about 20 different corals and 7 fish. The problem is, my coralline algae just won't grow!!!!!!!!!!! My calcium is almost to 420 now and I'm looking to get it up a little over 450. I am getting pretty good growth from my sps, but there is no new growth what so ever from the coralline, and I even had a few nicely covered pieces of live rock that I bought and it is slowly dying off! I don't understand why this is happening. I know phosphate inhibits the growth of Coralline, but I have no trace of phosphates in my tank! Any ideas?