i had the xm 15kl in my tank for 9 months. growth sucked. just recently changed to the ab (aqualine buske) 10k. growth has been outstanding. what i really like about the ab, is that altho, they are 10k, the color is closer to 12k. i have 260w of actinic as well. i like color combination, and the fluoresce doesn't get real washed out, when the halides are on.
jmo