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...