Fish and plants use different range of light spectrum, so two or three lights of different characteristics are usually combined to meet the requirements of each member of the aquarium.
Plants react differently to each type of light. A very important factor for plant growth is the color temperature of the lights. For example, warm light (around 3,000° K) stimulates growth in height, while cold light (around 6,500° K) stimulates lateral or shrub growth of the plants themselves. That's why the combination of both is ideal for full and uniform growth.
Some important references to be taken into account by the aquarist are the following:
A quick and simple way to calculate the light requirement of a fish tank is to provide 1 to 2 watts per litre of water. Of course, this is not a definitive formula, as other factors should be considered such as the specific requirements of each plant, the depth of the aquarium, the type of fish present, etc.
Another very important factor for the optimization of the lighting installation is the use of mirrored ceiling lamps or screens to achieve the reflection of light that would normally be lost.
Algae will take advantage of any kind of lighting to proliferate, so it will be of paramount importance that the aquarium is healthy. This means that if for any reason we have excess nutrients caused by reasons such as a huge biological load, insufficient filtration or fertilizer abuse, algae will gain ground in front of plants and what is commonly called an “algae explosion” can occur.
If this happens, the treatment can be quite traumatic, leaving sometimes irreversible consequences in the aquarium. Even experts in the field have their differences in this regard.
There are tubes that simulate daylight, albeit unsuccessfully. They are very expensive, last less and do not yield as much as the combination of tubes of different spectrum ranges and color temperature.
Another very important fact is that the tubes do not penetrate the water at more than 60 cm deep enough for plants to take advantage of this lighting, so in aquariums of greater depth should be complemented with other lights such as Hqi or Spots.
Spot light is used to illuminate a specific area of the aquarium. Usually because of the location of plants that require more light than others. They are not installed in the aquarium, but are hung pointing towards it.
Energy-saving lamps have become a very valid alternative to illuminate small planted aquariums. There are warm and cold light options that combined work very efficiently.
It is important to know that their service life is more limited than the manufacturers declare, since after six months of use their quality decreases noticeably and they need to be replaced. Its value is reasonable for the cost-benefit ratio.
A similar option of good results are compact U-shaped tubes, provided that their spectrum and color temperature are suitable for each case.
There are mercury vapor lamps much sought after by aquarists. Allows you to use spotlights with or without built-in reflector. Since the operating time is short, they are replaced every six months. They only agree if their spectrum is suitable, a rare thing.
There are those who use tungsten lamps because they are very economical and easy to install. But they are not recommended, as they are easily overheated and the accessories become dangerous. Your light spectrum is not very suitable.
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