I have four 65 watt pc bulbs on a 75 gallon tank. 2 actinic, 2 10000k, 2 50/50. Brand new bulbs. Coral is 1/3 up from bottom. I think they were under halides when i bought them. There has been coral in this tank for 3 years. Softies,and LPS. 120 lbs live rock, three inch sand bed, 20 gallon fuge, ASM protein skimmer, very good water flow. This tank is very well maintained. Nitrates below 5 on a Hagen test kit, and phosphate is barely detectible. All other corals doing great. These mushrooms are spread out and look good. The lights go out at night and the next morning there is another casualty. They turn into brown slime and disinigrate very fast. A power head will blow the dead ones off like they were never there. I also have a 150 gallon frag system. I grow green star polyps, yellow polyps, green trumpets, purple/green trumpets, purple, green, and orange zoanthids, pulsing xenia, and green mushrooms. Ive never encountered anything like this before. This hobby is a never ending learning experiance. The more i learn, the more I find out I dont know. Thank you for your help!