Coraline is was very slow in my tank - the 1st 4 months was like just little dots and brown diatoms grew like crazy - now however the coraline is growin' like a bat outta hell and the diatoms are dwindling. Perhaps it's because of the upgrade in salt from the cheapist instant ocean I could find to Red Sea's SPS/LPS salt raising alk, mag,+ calcium, perhaps it's the overall maturity of the tank, perhaps it's the daily different foods used for the reef - ie - reef snow (bacerioplankton), zoo+phytoplanktons, oyster eggs,+ blackpowder, perhaps it's the carbon dosing, perhaps it's the DIY R/O treating of the w/c and top off water - however I'm more inclinded to think it's a combination of ALL of the above.