Sitting or Hanging Hood

• Determine if the cover will be placed on top of a glass surface that covers the tank or if it will be suspended above the tank to allow for a completely open hood. The most common hood for fresh water aquariums is a hood that sits directly on top of the tank, but according the Aquarium Depot, the best lighting for a marine aquarium is halide lighting which is primarily used in hoods that hang above a tank.
  
  

Wood or Metal

• Most custom built tank hoods are built out of wood that matches the look of the tank stand. This gives a consistent look and helps to improve the overall aesthetics of the tank. However, many people opt for a ready-built enclosure and use their preferred electronics and bulbs. If you opt for a wooden enclosure, The Krib.com offers a well written guide to get you started.
  
  

Reflection

• Reflection is important in both florescent and halide lighting. Chrome plated sheet metal can be purchased from most home improvement stores. This works well when molded into the inside of a custom light hood and will reflect a sufficient amount of light. Reef Fanatic.com also states that polished aluminum can be used. Many retailers sell reflectors but they might not work if your enclosure is not a standard size.
  
  

Halide or Florescent

• The lights used in an aquarium hood are one of the most important ingredients for a successful tank. According to Marine Depot.com, florescent lighting works best with coral and invertebrates that require little lighting to thrive, and halide lighting is the preferred light for marine tanks that require large amounts of intense light. Badman's Tropical Fish.com also states that halide lights are the best lights for fresh water tanks but florescent are commonly used for their lower cost and availability.
  
  

Moonlighting

• Using lights that give a sense of moonlight have become very popular over the last few years due to the nutrients moonlight provides a reef. It encourages nocturnal fish to come out of their hiding places and helps to restore some of the natural aspect of a reef in the wild. Many people now incorporate moon lights into their hoods so they can provide sunlight during the day and moonlight at night.