Most people prefer to buy a plastic hood for their tank that includes a cover and lighting. Most packages contain either one or two fluorescent bulbs that are built in to the hood. This type of setup is very simple. You just place the hood on top of the tank, plug it in, and turn it on.
Standard normal-output fluorescent bulbs are perfectly acceptable for fish-only tanks, but they will not be able to support photosynthetic animals, and they will not be bright enough to accommodate other marine animals than need extreme amounts of light to survive.
Saltwater Reef Aquarium Lighting
If you intend to create a reef aquarium, your lighting needs will be different. For example, even placing a piece or two of live rock or soft corals will require you to replace at least one of the bulbs in your hood with a higher Kelvin normal-output bulb. A 10,000K bulb will usually be sufficient for some reed life, but only soft corals like mushroom coral (actinodicus) and sea mats would be able to live under the low lighting provided by two of these tubes.
Saltwater Aquarium Lighting - Types of Bulbs
There are four main types of fluorescent bulbs:
1. NO - Normal Output
2. HO - High Output
3. VHO - Very High Output
4. PC - Power Compacts (also known as Osram)
There is also another type of bulb altogether known as metal halide (MH). Metal halide bulbs are rated solely by wattage and spectral output. Since iodines and sodiums are not suitable for marine aquariums, you absolutely must avoid the type of metal halide bulbs that are found in commercial buildings and parking lots.
Saltwater Aquarium Lighting for Fish-Only Systems
For fish-only systems, standard fluorescent bulbs are sufficient. For reef aquariums, you need to ensure that you select enough watts for the number of gallons of water your tank holds. A 55 gallon aquarium, for example, would need at least 165 watts, and up to 275 watts in order for photosynthesis to effectively take place.
In order to get that kind of wattage, you might need as many as 4-6 fluorescent tubes, which is far more than any standard hood can accommodate. Thus for marine aquariums, one must generally choose VHO bulbs which require special ballasts. Or you could choose to go with metal halides instead.
Please note that a pre-made lighting system is NOT suitable for reef tanks. You will have to develop your own custom setup if you want the best possible solution. Some people use egg crates in their halide systems, but this is not advisable. A 250 watt halide bulb will melt egg crates!
Saltwater Aquarium Lighting - Metal Halide Bulbs
The trouble with metal halide bulbs is heat. They get very, very hot. You've probably touched a normal 70-100 watt light bulb in your house before. They get quite warm, but a 250 watt incandescent metal halide bulb will cause your tank temperature to rise precipitously.
Saltwater Aquarium Lighting Tips
You will need to make sure your hood keeps the bulbs at least 12 inches away from the water surface, ideally even higher. A distance of 15 inches would be better. This will allow some air to move between the bulbs and the water, but you will still need to use fans or a commercial chiller. Chillers can cost $500 or more, so this may not be a good option for you. But fans are acceptable for cooling if you cannot afford the added expense of a chiller.
About this Author
Denis Gardner discusses saltwater aquarium lighting and enjoys helping others get started in the amazing hobby of saltwater aquariums. His newest book, " The Ultimate Guide to Saltwater Aquariums ", teaches aquarists everything they need to know about starting and maintaining a beautiful, thriving saltwater aquarium.
Article Source: http://EzineArticles.com/?expert=Denis_Gardner
