Lighting systems requiring ballasts (continued)
HQI: HQI systems are relatively new to the hobby and offer many of the same features as the metal halides, but differ in design. The bulb is much smaller than the halides and is double ended. Many of the ballasts for the metal halides can also be used for HQIs. The HQI bulbs, however, require a system-specific socket. There is less of a variety of spectrums and wattages to choose from compared to the metal halides. HQIs are commonly offered in 150 watt and 250-watt systems with spectrums of 10,000K and 20,000K. Because of this, these systems are used mostly on saltwater reef aquariums.
Conclusion
Along with the many advancements that have been made in the lighting industry over the past decade, there has been a dramatic increase in our knowledge and understanding of the requirements of photosynthetic organisms. These two key factors have given us the ability to not only sustain many of these organisms in an aquarium setting, but also to raise and propagate them in an environment that is becoming closer to the conditions that occur in nature. When choosing a lighting system, it is important to design that system around the requirements of the organisms that are to be maintained.
