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Light plays several important roles in the aquarium. Obviously it is important for being able to see the fish and decor in your tank, but it also has a few other functions. For instance, lighting can provide energy to photosynthetic plants, corals and invertebrates. It can also affect the behavior of the fish in the tank through the length of day and night cycles. All of which can have a dramatic impact on the overall health and appearance of your tank and its inhabitants.

It is important to choose the right type of lighting for your aquarium, and with so many different types available this can often be confusing. The first step is to decide what the function of your light will be; is it for aesthetic purposes so that you can view your fish or is it for functional purposes to provide energy to tank inhabitants. Once you’ve determined this, you can then decide what type of lighting systems meets your needs. This will vary according to the type of tank you have and we’ve outlined some general lighting guidelines for particular types of tanks below

  • Freshwater or saltwater aquariums with fish only:Standard or Compact Fluorescent systems, and LED lighting
  • Freshwater aquariums with fish and/or plants:Standard Fluorescent, T-5 HO, Compact Fluorescent or Metal Halide/HQI systems, LED lighting
  • Saltwater reef aquariums with fish, corals and/or invertebrates: T-5 HO, Compact Fluorescent or Metal Halide/HQI systems, advanced LED lighting

Another factor to consider when selecting your lighting system is what type of hood or canopy you have or will need. Will most fluorescent strip lights will work with a full hood, more elaborate systems will require a glass canopy. No matter which type you choose it’s extremely important to make sure you have some type of barrier between your lighting system and the water.

Once you’ve selected the right lighting system for your aquarium and its inhabitants, the next step is to determine how long the light should be on each day. By setting a particular day and night cycle for your tank you are attempting to simulate the natural environment your fish would inhabit. The best way to accomplish this is by using timers to have your lights turn on and off at a specific time each day. Generally a light cycle of 10 to 12 hours per day is a good starting point; this can later be adjusted if you have inhabitants that require more or less light

The final consideration in aquarium lighting is bulb replacement. Even though a bulb still works, that doesn’t mean that it is delivering the same intensity or light spectrum that it did when new. In some cases having an underperforming bulb can even cause problems such as excess algae. In general, bulbs should be replaced according to the following schedule:

  • Incandescent Bulbs - Replace every 6 months
  • Standard Fluorescent Bulbs - Replace every 9-12 months depending on ballast type
  • T-5 HO Fluorescent Bulbs - Replace every 12 months
  • CompactFluorescent Bulbs - Replace every 12 months
  • Metal Halide Bulbs - Replace every 9-12 months
  • LED Lights - Never need to be replaced!