What percentage are you running it at ? Do you have a FTS shot with light on we can see ? I'm a self-proclaimed 'LED Snob' and IMHO the Kessil fixtures are very nice for a single point light source and more than capable of growing SPS in a Nano/Bio-Cube. What lighting were these Corals previously under ? If T5 they will indeed need to adjust to the single point light source and may have some loss of color underneath to begin with. A white Starboard or sand bed would help reflect light back up and may help.
