I am switching out my 8 bulb (60w each) t5 that I have had on my 265 gallon for the last few years. I have been spending close to $200 per year to change bulbs. So when I saw the deal for three of the 165w dimmable Marsaqua lights on ebay for $290 I had to say, "Why not?". My t5 is only 5 feet long and my tank is 7 feet, so the ends of the tank have always been kind of dark. I am hoping that these will help spread the light out a little better. I have a friend who swears by the things. I just built some custom hanging brackets. The lights should be here on Monday.