This aquarium light type uses semiconductor technology as its light source. A light emitting electrical diode.
The difficulty in developing LEDs for aquarium use, both reef and freshwater planted, is getting the correct wave length in light measurements called, nanometers and ultimately the usable light [PUR-PAS] of the emitters [PUR = Photosynthetically Usable Radiation. PAS = Photosynthetic Action Spectrum. Both are similar terms although PAS is more scientifically appropriate].
The picture above is of an office with many reef aquariums (which includes stony corals, SPS and LPS) set up with AquaRay LED lighting systems, please click to enlarge
Essentially, the best LED fixtures are NOT aquarium lights in the traditional sense, even the emitters are not a "bulb" as many people think.
High end LED fixtures use complex circuitry to evenly spread voltage over drivers and emitters to control each emitter precisely. Because of this, LED lights properly driven will not loose spectrum quality unlike ALL fluorescent lights, unless these emitters are daisy chained together, dimmed via linear or analog reduction, which is common....