@Xclusive Reef it is a 48x24x20 100g, it will have shimmer when water is in it.
@slief posted some videos of the lights over his frag tank which shows the shimmer, you can find it on Youtube if you search GHL Mitras, he has a few videos talking about them.
They are expensive, and if you do not like shimmer you might consider an ATI T5 fixture for your tank.

Most LED lights will have that shimmer due to being a single-point source of light versus the diffused approach of T5. I prefer the LEDs as T5 makes it look a little artificial in my opinion.