lighting

Light is the most important factor for good plant growth. Plants need the light as a source of energy to maintain their growth. Because most aquarium plants are tropical, they need more than just direct sunlight coming into the tank from your window or room lighting. In non-tropical countries, the summer sun is too bright and too hot. As a result, you get a lot of algae built up on your plants and in your tank. In wintertime, on the most part, it is too cold and the light is just too weak for the plants. With inadequate lighting and cooler temperatures, your plants become stunted.
Period of exposure to light in the tropical climates is between 12 to 14 hours all year long. In an aquarium, these plants need the same amount of lighting that they get in their native tropical climates. Therefore, you either have to put your lighting system on a timer or be faithful and turn your lights off and on for the required amount of time.
For fluorescent lights with a daylight spectrum, the rule of thumb is 1 watt for every two quarts of water. Energy efficient lamps have a higher out put. Spiral fluorescent tubes are substantially brighter than straight ones. The luminosity of lumilux tubes is about 30 % greater. For these lamps, .03 watts per quart of water is more than sufficient.