Reef aquarium lighting continues to be one of the hotly discussed and debated topics, as it is the most vital aspect of reef aquarium upkeep. Proper light intensity is essential for reef corals to carry out photosynthesis -- the process through which they create energy needed to survive and grow. Whichever approach and equipment you choose for lighting, the fundamental goal is to provide the reef inhabitants with a near natural lighting environment, made up of timed light exposure with proper intensity and light spectrum. This ensures the reef creatures have the greatest chance to thrive and flourish.

Lighting is generally expressed in watts per gallon. This considers the amount of light power dissipated over the volume of the aquarium tank. A good rule of thumb suggests that for low-light corals, lighting should vary between four and six watts per gallon. For light-loving reefs requiring higher light intensity, these should be bathed in ten watts of light per gallon.

An innovative method that simulates the path of the sun uses a multiple-light system with timer controllers to vary the number of lights that turn on at any given time. This is perhaps the most effective solution that closely re-creates the natural sunlight environment. In this system, one bulb usually stays lit for an hour, followed by all bulbs turning on for the next ten hours, and finally only the last bulb is lit for one more hour.

Two primary lighting solutions available in the market and commonly used for reef aquarium lighting are fluorescent and metal halide. Generally, fluorescent lighting would be cheaper and you should opt for this if your reef aquarium tank is not very deep. However, there are some reef corals like SPS coral for which fluorescent lighting does not provide enough intensity. Bear such points in mind while you weigh between these two popular lighting methods.

Fluorescents come in several types. There are the low-cost cool lights that are suitable for all-purpose lighting and these generally last for many months before requiring replacement. On the other hand, there are Power Compacts which use a modern twin-tube design that "bends" the fluorescent tube in half. This is somewhat a next-generation design that generates greater light intensity compared to standard fluorescent variants. Power Compacts typically last up to two years.

The other popular lighting option is metal halide, which is the most intense of all available lighting systems. If your reef aquarium tank is somewhat deep, metal halide is the better option as halides have greater capacity to penetrate depths beyond 20 inches. Metal halide lighting can beautify your aquarium tank too, by producing dazzling glitter lines. This can be seen as a useful bonus on top of the utility factor of metal halide-based lighting.

Steady advances in the light manufacturing industry have contributed to better reef aquarium lighting equipment that is more energy efficient. Depending on the type and standard of aqua life you want to keep in your reef aquarium, your lighting solution can vary in price from inexpensive to modestly pricey. Understand your aquarium tank and reef corals well to make an educated choice; you should be on your way to success in reef aquarium upkeep. Remember the first step: let there be light!