Deciding to build your own custom aquarium hood can set your aquarium apart from all of the other hobbyists' setups. However, several aspects must be decided on before you begin to construct the aquarium hood of your dreams. The type of lighting you want to use in the hood determines some of the necessary components that are needed to adequately light your aquarium.
Canopy or Compact
Canopy enclosures are the same dimensions as a tank. For example, a 10-gallon tank measures 24 inches by 12 inches. A canopy top for that tank will have the same outside measurements. This gives maximum room for lighting, ballasts and accessories to be hidden under the hood.
Compact enclosures are generally one-third of a tank's width. For example, the same 10-gallon tank would have a compact enclosure measuring 24 inches long by 4 inches wide. Use one of these on your tank if you need rear access for hang-on-back filters.
Hanging or Standing
Hanging lights are suspended from a ceiling or from poles mounted on the side of a tank and extend above it. They are mounted on chains and are good for tanks where no lid is preferred.
Standing hoods sit directly on top of a glass or plastic top. The glass or plastic protects the electronics from getting wet. These hoods focus more light directly into the water than a hanging light does.
Single and Multiple Lights
Compact enclosures require only one florescent light to adequately illuminate a fresh-water tank. However, reef tanks often require several florescent lights because they use daylight and moonlight bulbs. Reef tanks also tend to be larger in size, so more light is needed to adequately illuminate them.
A good rule of thumb is one bulb per 2 inches of hood enclosure. For example, a hood measuring 12 inches from front to back could have six florescent bulbs.
Sealing Wooden Enclosures
Treat a wooden tank hood with a wood sealer or hard-coat finish to protect it from water damage from the mist created by filters and in-tank air systems. The water and the salt in it can rot the wood. Use common hard coats such as nitrocellulose and polyester to seal the wood on your tank hood, and allow it to fully cure before using.