Aquarium lighting is a vitally important component of an aquarium display, without it the visual aspect of what may be quite a physically imposing piece of equipment remains dull and un-interesting. Lighting brings the display alive and allows us to delight in the reflected beauty of shimmering shoals and dramatic designs displayed by the myriad of fish varieties available to the home fish keeper. Lighting also plays an important role in ensuring plants are able to photosynthesize and in some aquariums such as the reef system, is essential to the survival of many types of invertebrate life forms.

Types Of Aquarium Lighting.

It is important to choose the correct type of lighting that will suite the type of aquarium system and the effect you are trying to create. The following are the most common types of lighting available.

Fluorescent lighting.

Fluorescent lighting is and has been for some time, the most common type of lighting system employed and despite many other innovations and introductions, still has a lot to offer the fish keeper. Many companies offer a choice of fluorescent tubes with the most popular (UK) being marketed by Hagen, Interpet and Arcadia. Standard fluorescent tubes (See also T5 tubes) are 1” (25mm) or 1.25” (38mm) diameter tubes of varying length from 12” (30cm) to 60” (150cm) and wattages (Power output) from 8 to 60 Watt. There is a correlation between the length of the tube and its wattage, for example all 12” (30cm) tubes are 8 Watt and all 24” tubes are 18-20 Watt. The tube terminates at each end with a metal cap and two projecting pins. The pins push into corresponding holes on a separate, plastic end cap that fits snuggly around the tube preventing moisture ingress. The end caps have wires running back to a transformer (Switchgear) that is positioned outside the aquarium, as it is not waterproof. The transformer has a switch for on / off operation. Most systems now use the 1” (25mm) diameter tubes and the larger diameter versions are gradually disappearing. All manufacturers produce tubes that give out different types of light and which of these to pick is the first choice faced by the fish keeper. If buying a manufacturers tank kit the tubes fitted will usually be the correct ones to achieve best results for the target aquarium type, but these may need to be replaced if you change the specification, i.e. convert a system intended primarily for Freshwater Tropical fish keeping, to Marine.

• Choosing A Fluorescent Tube For Coldwater Aquariums.
  Coldwater aquarium fish are, by nature, natural grazers as plant material forms a large part of their diet. As a consequence keeping a coldwater aquarium well stocked with plants is difficult as the fish insist on dining on your latest prize potted specimen. For this reason lighting is chosen mostly for its aesthetic affect and not for any positive effect it may have on plant growth. The predominant colours of many coldwater fish are shades of red and blue and choosing a light tube that will complement and even enhance these colours will achieve the best results. A modern florescent tube for coldwater systems will be biased towards the spectral output giving (To human eyes) a pinkish tinge but also be balanced with a white light output so that colours other than red and blue are not dimmed and distorted. Another benefit of these tubes will be reduced algal growth, which should keep any silk or plastic plant decoration pristine for longer. Examples of these are Hagen’s Aqua-Glo and Interpet’s Beauty light.



• Choosing A Fluorescent Tube For Tropical Aquariums.
  A Tropical Aquarium system will always look its best when fully planted with a lush growth of aquarium plants. If a successful under water garden is to be achieved, then the element of light is an important factor. In nature plant growth is stimulated by natural sunlight that penetrates the water to reach the plants below. A fluorescent tube for tropical aquariums in which good plant growth is required will, therefore, need to replicate the wavelengths of the natural spectrum that are able to penetrate water. These tubes are of a visibly brighter rendition to the ones used for coldwater systems and as they are more complex they are a little more expensive. Examples of these are Triphosphor tubes like Triton from Interpet and Power-Glo from Hagen.



• Choosing A Fluorescent Tube For Marine Aquariums.
  The bustling coral reef is teeming with life that has evolved under the intense glare of a tropical sun, much of which relies on this high light intensity to power basic life functions. The Marine system, therefore, has the highest light requirement of all aquarium types. For Marine systems a combination of two, three or more tubes is recommended, dependant upon the system type. A typical combination would include a daylight tube, which as the name suggests is even more complex than the tropical tubes above and produces a light output even closer to that of natural sunlight. These 4 band tubes are very bright indeed and are even more expensive than high output tropical tubes but are absolutely essential for success. Some tubes have an inner coating that acts as an in-built reflector further increasing brightness. Examples of these tubes would be Daylight Plus from Interpet and Life-Glo from Hagen. Combine these with an Actinic 03 spectrum tube such as Arcadia’s Marine Blue Actinic, Hagen’s Marine-Glo or Interpet’s Blue Moon. One Actinic to two daylight tubes is the usual combination. Less lighting is required for fish only systems and mixed fish invertebrate systems that do not include true corals and the more difficult types of Anemone and Polyps.

T5 Florescent Tubes.

T5 fluorescent tubes differ from traditional fluorescents as they have a smaller diameter and produce higher outputs, up to 80% greater. In addition they have a very long life of up to 20,000 hours, almost two and a half times that of other fluorescents. Also, very importantly, spectrum output is only reduced by around 10% (See also “Maintenance of Fluorescents” below) over the operating life of the tube. These characteristics make these tubes a good choice where high output is required and they are a very competitive in cost terms when compared with standard fluorescent (T8) tubes and Metal Halide lights. Arcadia produces a range of daylight white and Actinic T5 tubes in 24,39,54 and 80 watt outputs. Compact T5 tubes are also available from other manufacturers. It inconceivable that this type of tube will ultimately take over from other types.

Enhancing Fluorescent Tubes.

Greater light output can be achieved by fitting of reflectors. These can increase light output by 80 to 100% and are especially useful for deep aquaria where light penetration can be a problem. Clean reflectors regularly to maintain their reflective potency.

Maintenance of Fluorescent Tubes.

To ensure maximum light output at all times it is vital to clean the tubes on a regular basis. It is recommended that this be carried out every four weeks by gently wiping with moistened kitchen paper or cloth. Stubborn deposits may be removed with methylated spirits or a proprietary glass cleaner. Ensure that the tube transformer is switched off and the tube is cold before attempting any cleaning. It is a characteristic of fluorescents that the spectrum of light emitted changes and reduces gradually throughout the life of the tube. Some tubes lose between 40 to 60% of their output after only six months usage. It is important, therefore, to replace tubes at least every twelve months unless the manufacturers specification indicates that this is not necessary as low reduction of spectrum output over the life of the tube is a characteristic.

Metal Halide Lighting.

Metal Halide Lighting has for a long time been the lighting of choice for the serious reef system and provides an almost un-paralleled source of high intensity light output. The most common version is housed in a rectangular unit that is suspended above an open topped aquarium on stainless steel cables anchored to the ceiling above. Wall mounting brackets are also offered as an option from some manufacturers. The unit will often include Actinic tubes to further improve the spectrum coverage and penetration to greater depths. Metal Halide lights are the most expensive of all the light systems with prices from around £250.00 to over £1,000.00 (Pounds Sterling). There are also some very advanced versions of these lights available that have computer assisted functions such as simulated U.V. light output corresponding to a Lunar cycle (Believed to influence spawning of Corals) but be prepared to part with serious money if you intend to incorporate one of these into your Reef system. For maintenance of these units refer to individual manufacturers instructions.

Mercury Vapour Lighting.

Mercury Vapour Lighting is another high output light of large bulb like appearance housed in a suspended or wall mounted dome like pendant. This type of lighting is popular with specialist systems dedicated to fabulous plant growth. Like Reef systems, these aquarium types are open topped, often with plants breaking the surface, primarily plant displays with fish added only for contrasting colour and movement. This type of system is especially popular in Germany and the Netherlands. For maintenance of these units refer to individual manufacturers instructions.

Over-tank Luminaires.

Over-tank Luminaires are another suspended lighting system, which are becoming and marine systems. Some versions have brackets that attach directly to the end panes of the aquarium. Over tank Luminaires provide an exciting opportunity create a stunning open topped display aquarium for a reasonable cost. For maintenance of these units refer to individual manufacturers instructions.

It is important to spend time considering the lighting options for your chosen aquarium system to ensure you get the best possible combination. Filtration is often called the “Heart of the system” and should be allocated the Lions share of the available budget. Whilst this is true, Lighting should come a very close second and should not be skimped on.