I have two Metal Halide fixtures. One has a 250w MH w/ 2x96w PC's. The other has 2x250w MH's w/2x65w PC's. I was going to use these on two separate tanks but now i only have a 75g. I hung the the first fixture from the ceiling(6" from top of the tank) and it looks good. Light reaches every part of the tank. I use the 2x96w PC's for supplemental light. So that gives me 442 watts of light.(5.9w per gallon) If i switch to the second fixture would that be overkill? (630 watts, 8.4w per gallon) P.S i am using Phoenix 14000k HQI bulbs. Thanks in advance for any advice.