What is the best way to light an aquarium?

The aquarium should be lighted from the front and the top. The rays of the light should be directed down and back toward the rear, bottom. They should be directed away from the viewer’s eyes, striking the fishes directly to reveal their beauty. Light coming from the rear tends to silhouette the fish and to conceal refractive colors.

As a general rule, eight to ten hours of light a day, utilizing the wattages given, will result in satisfactory plant growth. Larger wattages may be used for lesser periods of time, and smaller wattages for greater. That there is a point of diminishing returns is obvious. Too low a wattage will not penetrate a depth of water; too high a wattage may overheat the upper layer of the water. Observation over a period of time will determine the most satisfactory wattage to use and the proper period of time to keep the lights on.

The most satisfactory arrangement is one that keeps the plants healthy and the algae growth down to a minimum. Should the plants start to deteriorate, usually more light is required; that is, higher wattages or a longer period of illumination.

Excessive growth of algae usually indicates too much light and, possibly, an excess of decomposing organic matter. The remedy, usually, is to decrease the amount of illumination and to siphon off all excess food and foreign matter. A certain amount of algae is bound to form even under ideal conditions. But you can keep this minimal growth in check by scraping and by using scavengers. You should be most concerned with the wild, seemingly uncontrollable growth that coats the rocks and plants and turns the water green.

Certain colors, although pretty to see, actually inhibit the growth of plants. The warmer tones at the red end of the spectrum are the most satisfactory for plant stimulation. Blue colors are the least helpful. The most practical are the uncoated clear glass bulbs which have a long filament. Although there are a number of inexpensive bulbs on the market which have short filaments, actual tests have proven them to be less effective than the long in stimulating plant growth. Any coating on a bulb must of necessity diminish the amount of light reaching the plants and thus decrease the effectiveness of the bulb.