Reef Lighting Information

Reef lighting is by far one of the most controversial topics when it comes to reef aquarium keeping. Because there are so many different elements involved in setting up your lighting, the topic is often hotly debated and is largely subjective. The bottom line is that animals kept in your aquarium will each have unique lighting requirements to help maintain their health---although aesthetic value of reef lighting is also important.

  1. Basics

    • For low-light coral, hobbyists often suggest that between four watts and six watts per gallon of water will produce adequate lighting. For light-loving coral varieties, as many as 10 watts per gallon may be indicated. This is a rough guideline, however, because the shape of the aquarium will also play a role in determining lighting needs. Aquariums that are taller rather than wider are going to require a greater intensity of light to reach corals near the tank bottom. Two tanks with similar volumes but differing heights and widths would have their own lighting needs. There are advantages and disadvantages associated with all types of reef lighting systems, though all can be configured to meet your needs.

    Fluorescent Lighting Options

    • There are two forms of standard fluorescent lighting used in the reef lighting hobby, normal output bulbs (NO bulbs) and high-output bulbs. These bulbs are defined by the amount of wattage used to illuminate the tube. A standard 48-inch fluorescent tube requires 40 watts for the light to be produced. A 72-inch fluorescent tube will require 55W. 36-inch fluorescent tubes require 30W, 20W is required for 24-inch tubes, 15W is required for 18-inch tubes and 8W of power is used to light a 12-inch fluorescent tube. Normal Output bulbs are commonly available, and they tend also to be inexpensive and fairly low in terms of heat output. They do not produce high light intensity, however, so they are not always ideal for reef lighting.

    Very High Output Fluorescent Lighting

    • Very High Output (VHO) fluorescent lighting tubes require special ballast capable of handling much higher requirements for wattage. They appear similar to Normal Output lighting, but their intensity and power usage is approximately three times greater. 18-inch tubes require 30W, 24-inch tubes require 75W, 36-inch tubes require 95W, 48-inch tubes require 110W, 60-inch tubes require 140W and 72-inch tubes require 160W in order to produce ample lighting. The high output of light provided by the VHO fluorescent bulbs are what make it a popular choice for reef lighting.

    Compact Fluorescent Options

    • Over the past few years, these bulbs have become more common among reef lighting setups. They employ technology similar to a VHO fluorescent light, but they are folded in half to create a U-shape rather than being a simple long tube with connectors on each end. A 55W compact fluorescent bulb is suggested to produce the same light output as a 95W VHO fluorescent tube. The main advantage of this type of lighting is that more wattage can be created in a smaller amount of space, which is why these bulbs are commonly referred to as being power compact. The light you can produce with these bulbs is quite bright, but sometimes it comes at the cost of an increase in heat, which you need to consider.

    Metal Halide Options

    • Metal Halide lighting is considered to be one of the ultimate types of lighting for reef aquariums as there are a variety of color spectrum choices and wattages to choose from. Any coral variety that loves light can be allowed to receive the proper illumination when the proper wattage is used. The main advantage associated with metal halide lighting is that the light bulbs are bright and therefore able to emulate natural sunlight. The downside is that they also produce a significant amount of heat. You could easily injure yourself if you only lightly touch the bulb, meaning that extra care is required when using metal halide bulbs. Metal halide bulbs are more directional in nature, rather than diffusing the light evenly across the length of the tank. The amount of light, then, can decrease when you move away from the direction where the bulb is facing.