Metal Halide Lighting vs. Compact Lighting

Lighting is one of the most complicated portions of setting up an aquarium. There are many different options when it comes to choosing a tank fixture, but two of the most widely used, especially for saltwater or reef tanks, are metal halides and compact fluorescent lighting.

  1. Intensity

    • Metal halides offer a much higher lumen per watt ratio compared to power compacts (PCs). Additionally, metal halides are also able to be manufactured at a smaller size than PCs for the same wattage, meaning more light in the same number of square inches.

    Efficiency

    • Metal halides are better at converting electricity into usable light, meaning that they provide more photosynthesizing power for the same amount of energy use.

    Spectrum

    • In general, compact fluorescent bulbs are available in a much wider spectrum than halides. Many aquarists find the average halide bulb to be too green or blue to be used alone over a tank.

    Drawbacks

    • Metal halides get much hotter than power compact lighting, and should never be used over open water without a splash guard, as the bulbs can potentially shatter if splashed due to extreme temperature fluctuation.

    Cost

    • Power compact lighting is much less expensive than metal halide lighting. PC lights are more widely available and more easily replaced. Initial setup with metal halides can be very cost-prohibitive.