I'm setting up a 30 gallon rimless frag tank and have decided to go with t5 lighting. I have SPS and some softies. Would a 4 bulb ATI fixture suffice, or should I go with a 6 bulb. Since it's only 12" deep, I'm leaning towards the 4 bulb. Thoughts and advise? I know it's a touchy subject, but is it worth it to go with the pricey ATI fixture or go in another direction?