mysteria
Joined: 23 Jan 2006
Posts: 21
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Hi everyone,
The illumination of an aquarium is something that's always present and often discussed. Very often mistakes are made and thus we're hoping to offer you some help by means of this article.
The lighting of an aquarium
Generalities:
The lighting is a very important aspect of a functioning and optically appealing aquarium. Due to the variety of lamps, it isn’t always easy to pick the ideal bulb, and one easily makes a wrong decision.
Sometimes, either the illumination isn’t adequate for the plants you wish to cultivate or the running costs are too high, or the light color isn't right, and so on.
Especially when regarding the expenses one shouldn't only consider the price of the lamp but also the operative costs.
Plants need light energy for growing. They absorb CO2 during the day and transform it into oxygen. For this process they also need light. On the other hand, most aquarium inhabitants don’t need that much brightness, which, on the contrary, can make them shy or even terrify them.
How long should I run my lighting?
The light's running length should basically go by the local conditions in the animals' original habitat.
The minimum length should be 10 hours, the maximum 14 hours a day. A lighting pause around noon is controversial. It might help fighting algae, but the results are by no means uniform. The pause should always last between 3-4 hours, longer or shorter hasn't proved useful.
In any case, this method doesn’t correspond to natural conditions; we all know that the sun doesn’t take a break.
Moreover, shrimp like to eat algae, therefore there shouldn’t be much trouble concerning algae in a tank inhabited by shrimp anyway.
Another thing in favor of a midday break is if you feed your shrimp in the morning and pause the lighting around noon, you will be able to observe the shrimp longer in the evening.
Recommendation:
For all those not especially interested in technical detail I'd like to give a short summary here. Most tanks inhabited by shrimp are rather small and densely planted with fast-growing plants that are easy to cultivate. Most shrimpkeepers own several tanks (watch out, you might become addicted!)
Thus you want to keep the maintenance costs low, and usually you have a rather simple illumination. T5 lamps are still pretty expensive in acquisition, so we recommend T8 three-band lamps (light range in the 800s; see manufacturers' websites for further information) combined with a ballast. Which light color you choose is simply a matter of taste; each color in the 800s range is suitable for your plants. Most commonly used are fluorescent tubes of the light range 840 or 840 and 865 combined. The number of lamps you run depends on the plants and the tank volume. Aquariums of up to 54l should be equipped with one tube, bigger tanks with at least two, depending on the actual size of the tank.
How to choose the right bulb:
When picking your lighting, you have to take several facts into consideration:
What's the height of your tank?
What's its volume?
Which plants do you want to cultivate?
Future inhabitants
Your personal taste
How much money do you want to spend?
Of course your taste is no one else's business. In the first place, however, the illumination depends on the plants and animals you want to cultivate. It’s no use choosing the cheapest lighting and then complaining about poor plant growth. Or, on the contrary, to exaggerate and get a nicely illuminated tank and as a result the fish become shy.
The larger and deeper the tank is, the more care has to be taken with its lighting in order to make sure you give the plants enough light to grow properly.
There are several ways to light a tank. Fluorescent lamps or high-pressure metal halide lamps are most commonly used.
Two different types of fluorescent lamps are available, T5 and T8. They mainly discern in diameter.
T8 lamps have a diameter of 26mm and are the most-used fluorescent lamps these days. The T5 is a derivative with only 16mm in diameter. T8 can be equipped with conventional or electronic ballast. T5 lamps are always equipped with an electronic ballast.
When using high-pressure lamps you have to decide between halide lamps (HQI) or mercury lamps (HQL). HQL lamps are not all that useful, judging from an economical point of view. HQI lamps have the same light yield at a lower cost and are available in different colours. HQL is an obsolete standard.
Types of lamps:
In my point of view, HQI or HQL lamps are exaggerated in most cases, I tend towards using fluorescent lamps.
The lamps available in pet shops are recommendable for an aquarium, though they are quite expensive. Lamps used in living spaces (Osram, Phillips) are as useful but far better priced.
Fluorescent lamps are available in several qualities und colors. Today the most common designation for lamps is a three-digit code. The first digit specifies the quality of the color rendering, the last two digits the color of the light
The most common qualities first:
Standard / basic: The first digit here is under 8, for example 740. Therefore the color rendering is worse than a lamp 8XX. Furthermore the lamps' luminosity continually decreases, and they have to be replaced after two to three years.
Three-band lamp: The first digit is an eight. The color rendering is pretty good and doesn’t lose that much luminosity during operation. They can be used until they fail. This type is level with the lamps used by the specialized traders. Every color is suitable for good plant growth.
Full-spectrum lamps: The first digit is a nine. These lamps reach the best color rendering. If you don’t like the color rendering of your current lamp, you should try one of these.
Unfortunately the excellent color rendering is at the expense of the luminosity. The luminous flux decreases by about 30% in comparison with an equal three-band lamp. They can be used until they fail. This type is level with the lamps used by the specialized traders. Every color is suitable for good plant growth.
Using special plant lamps isn’t necessary in my opinion, since the results achieved with fluorescent lamps are as good as for these special lamps. Moreover, these special lamps lose their luminosity pretty soon and should be replaced after a year.
Re the color:
The last two digits of the code are for the color of the lamp. Adding two zeroes tells you the color temperature, for example: 865 = three-band lamp, color temperature 6500K.
The color temperature doesn’t have anything to do with the brightness; it only reflects the color character of the lamp. To put it simply: the lower the color temperature, the more yellow it looks, or rather, the higher is the red. Daylight is around 3000 to 6000k. To reach color temperatures above 10000k you have to use special lamps, but these high temperatures aren’t suitable for tanks, they just further algae growth.
Ballast:
The ballast in fluorescent lamps limits the electric current in the lamp. Without limitation there would be a current increase and the lamp would be destroyed. As I've already said there are two types of ballast. Both have the same effect, but they achieve this target through different methods.
Generally, the electronic ballast is more advantageous. It needs less electricity, weighs less, doesn’t get as hot and the lamps don’t fail as quickly as with conventional ballasts. The only disadvantage is the higher price. I believe, however, that the price for electronic ballasts will decrease within the next few years.
Definitions:
Luminous flux: The luminous flux is the brightness of the lamp. The higher it is, the brighter is the lamp. It’s gauged in lumen. One lumen generates the brightness of 1 lux in an area of 1 square meter.
Brightness: This is the degree of brightness in an area, for example: in a room we have usually 100 to 500 lux, in the sun 85,000 lux.
Light efficiency: The light efficiency expresses the efficiency of a lamp. It’s gauged in lumen/watt. The higher this value, the more electrical energy is converted into light. Fluorescent lamps get up to 85-105 lumen/watt. In theory, the maximum is 683 lm/W, but at the moment this value is far from being reached in practical use. However, your light shouldn’t even reach that value, because it wouldn’t be “white” then. The maximum value for white light lies at 199 lm/W.
Character: The character of the color is the same as the color temperature, but the character is described with words, for example white;
Color rendering: The color rendering tells us how good the color of the illuminated thing is rendered. The better the color rendering, the more natural the item looks, in our case the animals and plants.
Explanation:
This article represents my knowledge (at present date). If there are errors or omissions, I’d be happy to hear about them.
I can be reached here: http://www.crustaforum.com
My nick: Chrisp
This article has been translated by Stephanie Weigl and Ulli Bauer |
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