Lighting in aquarium plants has the same role as the sun in natural ecosystems. Natural sunlight is hard to utilize in an aquarium depending on the place of installation or due to the fact that the intensity and duration of sunlight cannot be controlled easily. If strong, direct sunlight shines into an aquarium, algae may grow on aquatic plants. Phytoplankton also tends to proliferate and this results in green water. Therefore, artificial lighting becomes necessary. However, it does not mean that just any light will do.
Besides providing light to aquatic plants for photosynthesis, lighting has another purpose of illuminating an aquarium beautifully for viewing as well. The colors of aquatic plants and fish do not appear beautiful with a red grow light designed for terrestrial plants or lights intended for indoor lighting. An aquarium requires the light that makes a layout appear beautiful and still promotes photosynthesis.
Lighting for aquatic plants
Nature Aquarium Lamp (NA Lamp) was developed for growing aquatic plants beautifully and displaying a layout attractively. The white color of normal fluorescent light is produced by mixing three primary colors of light: red, green, and blue. Various shades of white light, from reddish white to bluish white, can be produced by mixing varied amount of the three primary colors of light.
While many plant grow lights emit red light, red light diminishes rapidly in water and therefore is not very effective in growing aquatic plants. As it turns out, a blue light passes through water very well and promotes the photosynthesis and growth of aquatic plants. However, since the colors of aquatic plants and fish do not appear pretty with a blue light alone, red and green lights need to be added in a good balance while increasing the proportion of the blue light. Through various trials and errors, 8000K color temperature was adopted finally for the NA Lamp.
The NA Lamp that promotes the photosynthesis of aquatic plants and has a high color rendering ability at the same time made it possible to create beautiful Nature Aquarium. The concept of this light for aquatic plants was applied to metal halide lamps as well as fluorescent lamps.
Nature Aquarium Lighting
It is necessary to provide a sufficient amount of light to Nature Aquarium where beautiful layouts are created by growing aquatic plants densely. The intensity of light that is suitable for growing aquatic plants depends on the type of aquatic plants. Since heliophytic aquatic plants that demand bright light are often combined with sciophytic aquatic plants that can be grown without a lot of light in a layout, the intensity of the light is normally matched with the requirement of the heliophytes as much as possible. In the case of fluorescent NA lamps, the lamps are installed basically by covering the top of an aquarium with them. (For example, four-20W lamps for a 60 cm aquarium, six-32W lamps for a 90 cm aquarium, etc.) In the case of a metal halide lamp, one NA Lamp (MH-150W) can illuminate the entire 90cm aquarium with bright light.
Fluorescent lamps and metal halide lamps have different characteristics in the way that a layout appears under them. Fluorescent lamps envelop the entire aquarium softly with light without casting much shade, and therefore stem plants appear especially beautiful. On the other hand, a metal halide lamp shines directly and casts well-defined shadows. It is good to keep such properties of light in mind when planting aquatic plants.
Grand Solar I can recreate the light environment that is ideal to Nature Aquarium by switching or combining the intense light of the metal halide lamp and the softer light of the power compact fluorescent lamps. The metal halide lamp and power compact fluorescent lamps are both produced to NA lamp specifications.
Lighting fixture installation
Since Solar I for a metal halide lamp is a pendant type fixture, the space above an aquarium is open and the water surface is visible. This enables an open top aquarium in which driftwood and aquatic plants can protrude above the water surface. Since the water surface is visible, it not only creates a feeling of openness but also makes it easier to do the daily maintenance such as feeding and fertilizing and other maintenance such as water changes and trimming. Pendant type Solar II and Grand Solar II with power compact fluorescent lamps or Grand Solar I that combine the characteristics of a metal halide and fluorescent lamps are also available. However, one must note that a pendant type light fixture must be installed with a special stand or be hung from the ceiling directly.
Proper brightness for an aquarium
In the case of a pendant type Solar I, the standard distance between the water surface and the fixture is 30 cm. The brightness can be adjusted by changing the distance from the water surface. Solar I is typically used for a 90 cm aquarium. If more light is required over the entire aquarium, Grand Solar I is recommended. Grand Solar I comes with one 150W metal halide lamp and two 36W power compact fluorescent lamps, which can be lit at the same time or individually.
The light of an NA lamp has a high transmittance in water. It is fortified with the blue spectrum and with the wavelengths that chlorophyll absorbs well to promote the photosynthesis of aquatic plants. Additionally, it reproduces the natural colors of aquatic plants and tropical fish realistically. The green color of aquatic plants appears vivid especially because of the peak that is indicated by the arrow on the spectral distribution chart.
Lighting period
The light period of 8 to 10 hours per day is considered optimum for Nature Aquarium empirically. If the lighting period is shorter than this, aquatic plants don’t grow well or stem plants tend to get leggy. On the other hand, if it exceeds 10 hours, algae tend to multiply or aquatic plants stop photosynthesizing even when the light is still turned on.
Aquatic plants generally grow well if the light is turned on regularly every day during the daytime hours. An irregular light period can affect their condition adversely. In addition to being very bright, the metal halide lamp and power compact fluorescent lamps on Grand Solar I can create a near natural light environment since they can be controlled individually (the two fluorescent lamps operate simultaneously).
A time period in which light penetrates water so that it is bright enough for aquatic plants to photosynthesize in nature is rather limited. There are time periods before and after the brightest period around noon in which the light intensity is lower. To recreate these conditions in an aquarium, the lighting period of the power compact fluorescent lamps of Grand Solar I should be set to 10 hours and that of the metal halide lamp to 6 to 8 hours within the lighting period of the power compact fluorescent lamps.
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