I had moved this coral down lower in the tank for several weeks thinking maybe it was getting too much light, but it progressively got worse. During this time I started noticing a couple other corals starting to lose color and found my nitrates and phosphates continued to decrease down to zero. I eventually turned off my GFO reactor to bring up NO4 and started dosing potassium nitrate to bring up NO3. I'm now keeping them at 2ppm NO3 and 0.06ppm NO4. The other corals have improved coloration, but the forest fire did not recover and was too far gone. I'm thinking it was the canary in the coal mine indicating the nutrients were getting too low. Lesson learned.