Based on your previous posts, you seem quite intent on keeping soft corals like mushrooms, leathers, button polyps etc. A 150W halide can be very directional in that light is concentrated directly down over the tank. T5's give a nice spread of light that would cover the entire tank alot better than a single 150W halide would. Having 3 x T5's (at 54W each) is about the same wattage as the single halide. While the lux might not be as high, it may be more aesthetically pleasing as well as sufficient for soft corals. It depends what look you're after vs how much you want to pay. If price is a factor, then the problem with getting 3 x T5's is the electronic ballasts can only run 2 x T5's per ballast (well, the only ones I've seen) Also, you HAVE to run two T5's off that ballast, you can't just run one it wont work. This would mean you either go 2 x T5's or 4 x T5's (i just thought about this after my previous post!) If 4, then the price obviously increases. You can pickup single 150W halides for around $80 - $100. Four T5's would be more than double this.