Light is made up of particles of energy called photons, which create waves or wavelengths of energy. How intense the light is in your aquarium depends on the lux ratio, a measurement of light from its source to the bottom of your tank.
There are basically two types of aquarium lighting — fluorescent and incandescent.
Fluorescent lights involve the transmission of rays of mercury vapor. These cause the inside of a chemically-coated light bulb to glow. Fluorescent lighting is praised in aquariums for several reasons:
Very efficient – Initial price is expensive. However, bulbs usually are included with fluorescent units. At home, fluorescent lighting uses less electricity, so it’s cheaper to operate. They last much longer than incandescent bulbs.
Tank temperature constant – Fluorescent lighting gives off very little heat, and bulbs are cool to the touch. Hobbyists will not have to worry about aquarium water temperature rising and falling.
Fish colors bright, algae controlled – Fluorescent lighting emits light wavelengths similar to natural sunlight and will show all the beautiful colors of fish. They also help control algae growth.
Incandescent bulbs involve the transmission of electrons. These cause a bulb’s filament to burn, giving off light. Incandescent bulbs often are used for aquarium lighting, but aren’t generally preferred by most hobbyists:
Not efficient – Initial price is inexpensive. However, bulbs usually aren’t included with incandescent units and must be purchased separately. At home, incandescent lighting uses more electricity, therefore costs more to use. They need to be replaced more often than fluorescents.
Tank temperatures fluctuate – Incandescent lighting gives off alot of heat and can raise the temperature of the aquarium as much as 10 degrees Fahrenheit. So when the light is turned off, the temperature can drop as much as 10 degrees, which can cause severe stress in fish.
Fish colors suffer, algae grows – Incandescent lights only emit certain wavelengths of light and will not show the beautiful reds, purples, and blues in fish. They may cause excessive algae growth.
Different types of light should be tried in your tank for extended periods before deciding which works better. Fish, invertebrates, and plants all have different light requirements. As a general rule, most fish should receive 15 to 16 hours of light per day. Plant life does well with eight hours. As each tank and its inhabitants are different, the following light information is only meant to serve as a guide:
Blue lights help keep marine algae and invertebrates healthy in deep tanks.
Yellow and red lights work best in shallow marine waters.
Freshwater species flourish better under a full-spectrum bulb that closely mimics sunlight.
Pink and blue bulbs have been shown to enhance fish colors.
A wide spectrum yellow bulb can give aquariums a more natural look.
Wide-spectrum blue bulbs enhance algae growth in marine setups and provide daylight conditions for saltwater fish.
Full spectrum lights with blue bulbs are beneficial to corals, anemones, and inhabitants of reef systems.
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