aquarium reef tanks

Aquarium Lighting

Aquarium Lighting

Another hotly debated topic is aquarium lighting. With the advent of newer better methods, increasing intensities and a growing spectrum—the topic of aquarium lighting can be a daunting one even for the seasoned aquarist.

Many, if not most aquarium corals contain within their tissue the symbiotic algae called zooxanthellae. And it is these zooxanthellae that require light to perform photosynthesis and in turn produce simple sugars that the corals utilize for food. Therefore, the simple answer to light is to provide enough to maintain a thriving population of zooxanthellae in a corals tissue.

In practice however, this can prove to be a very complex issue. Some corals such as the Mushroom Coral require very little light to thrive – conversely, Acropora Coral, brain coral, Bubble Coral, Elegance Coral, Cup Coral, Sun Polyps Coral, Torch Coral, Trumpet Coral can require substantially more intensity. Of the various types most popular aquarium lighting comes from metal halide, very high output or VHO, compact fluorescent and T5 high output with many aquarists abandoning T12 and T8 fluorescent lamps due to their poor intensity and mercury vapor due to a limited light spectrum.

The next issue with aquarium lighting is the various terminology used in the hobby, such as color temperature measured in kelvins, color rendering index (CRI), photosynthetically active radiation (PAR) and lumens. Then the various power ratings available from a meager 9 W fluorescent lamp to a blinding 1000 W metal halide. The penetration of light by each bulb type (listed in order of weakest to strongest they would be: T8/12 or normal output lamps, VHO, compact fluorescent, T5 high output and the deepest penetrating bulb the metal halide). And to further complicate matters, the various types of ballasts available (electric ballast, magnetic ballast, and pulse start ballast).

Luckily the choice of which lights would be most appropriate for a new reef tank is to first choose what types of corals they plan on keeping. From that point the list shrinks considerably.