Lighting:
Hambani Aquatica aims at supplying State-of-the-Art Lighting Systems.
Our systems can include built-in ballasts for fluorescent lamps, metal halide lamps and moonlight.
Any combination of lighting can be designed for your aquarium and met to fit either your existing aquarium or a new aquarium.
How much light?
The amount of light required depends on what type of livestock you want to keep.
If you would like a greater variety of species, and possibly a more natural looking aquarium, metal halide or a metal halide/fluorescent combination would be more desirable. Metal halides will give the water column the same glitter effect as the sun, and also enable your system to support higher light loving corals.
As a rough guideline, a low to medium light system uses 2-5 watts of light per 5 litres, and a medium to strong lighting system uses 5-10 watts per litres. Corals requiring low light can be kept in stronger lighting systems, but may have to be positioned accordingly.
How many metal halides do I need for my sized tank?
The quantity of metal halide bulbs is first determined by applying the "watts per gallon" guideline (see question/answer above), and then by the length of your tank. For evenness of light colour across the length of the aquarium, approximately one metal halide per 60cm of tank length is suggested. If evenness of light is not necessarily required or desired, a 6-foot tank may be maintained with only two metal halides, resulting in "shadier" zones toward the ends.
What is colour temperature?
Colour temperature, or degrees Kelvin (°K), is a number assigned to a bulb to describe the colour of light it emits. The lower the number the warmer or more to the orange/yellow side of the light spectrum is its appearance. The higher the number, the cooler or more to the blue side of the light spectrum.
Is heat from lighting detrimental to my aquarium?
Heat is not a problem when using fluorescents. Heater settings may need to be adjusted up when adding a metal halide lighting system in order to narrow the daily temperature fluctuation. One can also provide ventilation in the area of the aquarium where the lighting is placed.
How long will my bulbs last?
Fluorescent bulbs should be changed every six months and metal halide bulbs every six to twelve months depending on the bulb type and number of hours specified by the manufacturer and coral requirements.
What type or style of lighting system is best for me?
Personal preference, long and short term goals for your aquarium and budget all play a factor in determining what is best for your lighting system needs. When you are ready to make those decisions, we hope you’ll give us the opportunity to offer our solutions to your lighting needs.
Glossary of Terms with direct relation to lighting:
Photosynthesis is a biochemical reaction in which carbon dioxide, water and light energy ultimately produce oxygen and carbohydrates; it is a link between the inorganic and organic worlds. The rate of photosynthesis is generally proportional to the amount of available light. Light quantity (intensity) and quality (spectral composition) are important for plant growth.
The photosynthetic electron transport system in all oxygenic organisms is composed of Photosystems I and II. Both systems include special forms of Chlorophyll A – Photosystem I include a form of the Chlorophyll A pigment with a specific absorbance of 700 nm (red light) that is called P-700. Photosystem II contains the reaction center responsible for oxygen evolution; it contains a special Chlorophyll A that absorbs light at 680 nm (red light) that is called P-680. Photosystem I is dependent upon the proper functioning of Photosystem II – if the photochemical reactions in Photosystem II are inhibited, Photosystem I is inhibited as well.
Zooxanthellae contain chlorophylls A (both P-680 and P-700 in addition to “regular” Chlorophyll A that collects light in the violet, blue and red portions of the visible light spectrum). Pigments that harvest light energy outside of 680 nm and 700 nm and make it available for photosynthesis are called Accessory or Antennae Pigments. Antennae pigments include Chlorophyll C2, peridinin and beta-carotene. Botanists and phycologists use terms with which one should be familiar. These include:
Photosynthetically Active Radiation (PAR): A measure of visible light intensity (400-700 nm) obtained by using a quantum meter. PAR is simply a count of photons falling upon a surface in a given time and is reported as “micro Mols per square meter per second” (µMols•m2•sec). Quantum meters report all wavelengths between 400 and 700 nanometers. However, they report only light intensity and do not account for spectral quality. Generally, maximum solar PAR values are 2,000 – 2,100 µMols•m2•sec. PAR is something of an outlaw in the scientific community; it is not recognized as a standard unit, however most major works in the field (notably Kirk (1983), among others) state compensation and saturation points (see below) in PAR units. (Since PAR is a relative new-comer to science, it has not been recognized by CIE ( Commission Internationale de L’Eclairage) or the International System of Units (SI) – both had already adopted standards for measuring light intensity. Lack of recognition by either of these committees should not undermine the importance of PAR measurements. Incidentally, divide µMols•m2•sec (of sunlight) by 4.6 to convert to watts per square meter per second (which is a SI-recognized unit.) A quantum meter is better suited for reporting light intensity than lux meters. Lux meters are photometric in their response, that is, they “see” light as the human eye does and have a maximum sensitivity to green wavelengths. The human eye is not especially sensitive to those wavelengths known to promote photosynthesis (violet, blue and red). Generally, noontime lux measurements made on cloudless days in the tropics range from 100,000 – 120,000 lux.
Maximum PAR is the highest measurement made under standardized conditions (for our cases, the lamps are 3.5" above the PAR sensor. This replicates the distance from the lamp to aquarium water surface in many cases.
Blue PAR is determined by using the PAR sensor and subtracting glass cut-off filters. A yellow filter removes blue wavelengths, red removes green, and blue removes red. The amount of radiation subtracted is added together and the "blue" PAR is divided by the sum of all 3 to arrive at an approximation of broadband PAR in each case. (These are exact, but since all lamps are tested under the same conditions, it allows us to compare lamps.)
Compensation Point is usually defined as the minimum amount of light required for oxygen production to meet the Zooxanthellae / coral host respiratory requirements. Corals have the ability to absorb oxygen from the surrounding water (as they do in darkness); however, insufficient light energy may also result in low production of photosynthetic lipids. During periods of prolonged darkness (or inadequate light) Zooxanthellae will then use their energy reserves until they are depleted and a sort of starvation occurs, usually resulting in irreversible damage or death. Compensation points vary from specimen to specimen and often depend upon their light history. Compensation points in low light adapted corals may be just a few µMols•m2•sec or much higher in high light adapted corals (350 µMols•m2•sec or ~17,500 lux; see Kirk, 1983). It should be understood that light intensity should exceed the zooxanthella’s compensation point.
Saturation Point: Photosynthetic rates are proportional to light intensity only to a certain point. The Saturation Point has been met when photosynthesis is at a maximum, and increasing light will no longer increase the rate of photosynthesis. Saturation occurs when the photosynthesis electron transport systems are operating at full capacity. Exceeding the saturation point is pointless, and from a practical standpoint, results in needlessly high electric bills. If light energy greatly exceeds the saturation point, Photoinhibition may occur. Photoinhibition is generally defined as any occurrence interrupting the normal electron flow in photosynthesis. There are two types of Photoinhibition – dynamic and chronic. The first is chronic Photoinhibition that involves irreversible damage to Photosystem II and were synthesis of new “photosynthetic proteins” must occur before normal photochemistry may resume (Brown et al, 1999). Dynamic Photoinhibition involves reversible photochemical reactions that divert excess light energy away from Photosystem II through thermal dissipation. This “quenching” of photosynthesis involves reversible changes in xanthophylls diadinoxanthin and diatoxanthin. Dynamic Photoinhibition protects the Zooxanthellae (through absorption of violet through yellow-green wavelengths of 400-550 nm) from high levels of photosynthetically produced oxygen radicals, including hydrogen peroxide. Not all strains of Zooxanthellae have the ability to produce xanthophylls and therefore may have little resistance to the effects of high light intensity.
Watts or wattage: A watt is a unit of power equal to one joule per second. Wattage is the amount of electrical power, expressed in number of watts, or the electrical power required by an appliance or device. Lamps come in various wattage ratings, with the wattage of the particular lamp describing how much electrical power a bulb or tube uses, but not how much light it generates. Different bulb technologies produce differing amounts of light per watt -- or, more technically, different bulb types are more efficient at converting electrical energy into light energy.
Joule: The unit of energy equal to the work done when a current of 1 ampere is passed through a resistance of 1 ohm for 1 second.
Lumens: The total amount of light that a lamp is capable of generating, usually available on either the lighting package or from the manufacturer's data sheets. There are two values usually quoted for fluorescent tubes: initial lumens and design lumens. Initial lumens describe how much light it produces when first turned on. Design lumens describe how much light it will produce for a much longer term. After an initial 20 percent drop in brightness, the light output will slowly decrease over the lifetime of the tube.
Lux: A unit of measure equal to lumens per square meter -- or, a measure of the actual intensity of the light falling over a specified area. Because lux depends on how the light gets from the bulb to the area, it cannot be specified by the manufacturer, but must be measured by the aquarist.