Understanding the Lighting Spectrum
Many aquarium hobbyists do not understand the basics of aquarium lighting and they end up purchasing the wrong bulbs or the wrong lighting system entirely. While having the right type of lighting in a freshwater tank isn’t quite as critical as it is in a reef tank where corals are present, it is still very important. The type of lighting you choose will have an impact on how your tank looks and how well the photosynthetic organisms in your tank thrive. When it comes to selecting the lighting for your tank you need to think about more than just wattage – you should also consider the spectrum of the lighting. Unless you understand the basics of the lighting spectrum you may be easily confused or overwhelmed when you set foot in the lighting section of your local aquarium supply store. This article will provide you with all the basic information you need to know about the lighting spectrum so you can make an informed decision for your tank.
Measuring Spectrum
The word spectrum, in terms of aquarium lighting, generally refers to the visible spectrum of light. Visible spectrum is measured in nanometers according to the wavelength of light energy. The wavelength for light visible with the naked eye ranges from around 400 nanometers to 800 nanometers – ultraviolet light is near the low end of the spectrum and infrared light near the upper end. If you look at a diagram of the visible spectrum of light you will see that it is often accompanied by a color scale. Light spectrum can also be described in terms of color temperature which is measured in degrees Kelvin. The color temperature scale was determined by heating a “blackbody” – the color of the body as it is heated to different temperatures corresponds to the colors on the scale used to describe visible spectrum. For example, at 0 degrees Kelvin the blackbody is black but, as it warms, it changes to red then yellow, green, blue and finally violet.
Types of Lighting by Spectrum
If you have ever spent much time in the aquarium lighting section at your local pet store, you have probably noticed the way bulbs are labeled. You probably saw words like “actinic” or “daylight” accompanied by a Kelvin rating (measured in degrees Kelvin). Actinic bulbs produce light from the blue end of the spectrum – this type of lighting is recommended for saltwater reef tanks because blue light is able to penetrate deep water better than regular white light. Full-spectrum bulbs, or daylight bulbs, produce light from all wavelengths of visible light which produces an effect similar to that of natural daylight. This type of lighting is good for all types of aquariums, both freshwater and saltwater. You may have also seen the term 50/50 or actinic white used – these terms are used to describe bulbs that produce a blend of white and blue light which is ideal for encouraging photosynthetic coral growth. Bulbs that are labeled “color-enhancing” typically produce light from the warmer end of the spectrum and they too can be used in either freshwater or saltwater tanks.
Spectrum VS Intensity
When researching aquarium lighting you are likely to come across the term “intensity”. The intensity of a light bulb can be measured either in lux or watts – wattage is the more commonly used measurement of the two. The higher the wattage of a bulb, the more intense the light it produces – higher wattages also require more energy to produce light. When you are selecting the lighting for your freshwater aquarium you need to consider the spectrum as well as the intensity of the lighting. Both the spectrum and intensity of the lighting required for your particular aquarium will be determined by the size of your tank and the type of tank inhabitants. Deeper tanks, for example, require more intense light and tanks that are stocked with corals may benefit from actinic light bulbs. Generally, however, full-spectrum bulbs are sufficient for the standard freshwater tank. You may also need to think about the wattage for the bulbs you select – larger tanks will require a higher wattage, as will planted tanks.
If you are just starting out in the aquarium hobby you may be overwhelmed by all of the things you don’t know. How do you select the right equipment for your first tank? What type of lighting do you need? These questions can only be answered with careful research. If you hope to cultivate a healthy and thriving freshwater aquarium environment, you should take the time to perform this research so you will be as educated and prepared as possible when it comes time to setup your tank. Do not be afraid to stop in to your local pet store to ask for help or suggestions but make sure to do your own research when it comes to choosing aquarium lighting. Every tank is different and the type of lighting that is best for one tank might not be best for yours.