I used to use biopellets, GFO, and carbon previously. After about a year of this, coral health was like a bell curve. Nothing much for a couple months, then at about the 6 month mark, colors were spectacular. Almost fake they were so vivid. Like alot of those zeovit ultra photoshopped tanks you see. Then after that, they just started fading. Acropora all became very pale despite feeding enough to sustain a small army. Zoa and LPS growth slowed to a halt, then acropora began to STN. I removed the GFO instantly. Observed and saw little improvement. After seeing the STN begin to claim full colonies, as well as frags I tried to save, I pulled the biopellets as well instantly. Over the coming weeks algae exploded in the tank. Added a foxface and a few emerald crabs. Eventually the pump to my carbon reactor died so I pulled that too. Algae phases came and went and now the tank is virtually algae free minus some 2mm or so tall red turf on a few rocks. Nitrate still undetectable, but phosphate up to 0.02 ppm or so. Zoa and LPS growth has really started to take off. Acropora colors have returned, albiet a little browner and more natural looking. Polyp extension is fantastic though and my growth is faster than ever.
I imagine one day phosphate and nitrate may creep back up in this tank, but as of now...I had to remove the media reactors. They worked great at first but began killing the tank. I attribute the improvement in health directly to removing them.
