USHIO Aqualite™ Metal Halide lamps feature the best combination of color balance, color rendering and photosynthetic light output for healthy marine aquarium and reef systems. Our USHIO BLV factory in Germany, collaborated with leading marine biologists to develop the first 10,000K Metal Halide lamps. We have successfully set the benchmark of quality for over ten years.
Different wavelengths of light are absorbed at different rates by water. The red and infrared (IR) energy which have the longest wavelength and therefore the least amount of energy in the visible spectrum do not penetrate the water very far and are quickly absorbed at the surface. A red fish swimming near the surface will appear red and vibrant but that same fish at lower depths will appear black since there is no red light to reflect off of it. Next is orange, yellow, green, and then the blue region around 450nm which reaches the furthest.
Although it has the shortest wavelength and highest energy, ultraviolet light is also quickly absorbed from water. The smaller wavelengths of light are easily scattered by particles in the water.
The difference between natural light at a few meters below the surface and artificial light can be quite dramatic. Professional dive photographers use xenon strobe lamps at 6,000K daylight color temperature to best show off the colors of coral and marine life as we would prefer to see it. You can see how quickly the color of the corals and fish enhanced by a xenon strobe fall off and everything turns blue in the background of professional underwater photographs. Colors of the reef and fish that are enhanced under the artificial light would normally have a monotone cast to it under natural light at that depth. This is why artificial light in reef aquariums can be very subjective when it comes to color rendering. The choice of lamp color temperature is tied to the individual aquarist’s eye when other factors such as PAR ratings and coral growth are ruled out.
