My understanding of uv lights is this: anything in the range of 10-400 nm can be considered uv. While uv light used for sterilization is typically in the range of 200nm(uv sterilizers for aquariums are around 250nm) , what we consider uv for reef lighting is much higher. More in the 360-385 nm range. And while this is still in the uv range, its actually closer to a true violet. At this range, it provides par that is used by coral so while see the benefits as more towards just being aesthetically pleasing, it actually serves a purpose. Just my 2 cents..