ReefLux is the first true 10000K full spectrum metal halide bulb to be offered to the aquarium market. Other manufacturers claim to offer a 10000K lamp but that is just a marketing number of their best attempt to offer a full spectrum 10000K lamp. This is why they have a yellow or orange appearance and need to have some kind of fluorescent actinics to balance it out. Generally the more yellow or orange a bulb the more PAR the bulb will produce. ReefLux offers you the highest PAR rating without having to flood your aquarium with high powered fluorescent blue bulbs.