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Aquarium Hood Light Not Working?

Aquarium Hood Light Not Working

The aquarium hood is essential to your tank setup, but it can be infuriating when the light refuses to work correctly.

The most common reasons why your aquarium hood light is not working are that the bulb has blown, the light fixture is loose, the starter needs replacing, or there is a problem with the ballast. Knowing how to identify and fix each of these problems goes a long way in maintaining a healthy aquarium.

Continue reading to discover why your hood light isn’t working and how to address each issue.


Reasons Why My Aquarium Hood Light Is Not Working.

The hood is essential in providing adequate light and ventilation to your tanks. If part of the hood fails, it can cause severe problems for your fish. Inadequate lighting can cause algae growth, while improper ventilation causes bacterial growth through stagnant water.

In addition, insufficient lighting can stunt plant growth and cause fish to become pale or diseased.

There are several reasons why your aquarium hood light might not be working. The light connections could be loose, the light itself may not be secured in place properly, or the starter may need to be replaced.

The solution is obvious – you need more light. The method for achieving this is not always so obvious, though there are several ways you can try to fix your tank. 

How Do I Fix My Aquarium Hood?

The first step in fixing your aquarium hood is to determine the problem.

Firstly, check your electric supply with a tester. Secondly, check for any loose connections to the bulb; these could be at the starter or the pins in the tube holder.

Keeping a few essential tools handy is a great way to fix your hood light efficiently. You can fix many common problems with just a screwdriver, pliers, and wire cutters.

Try reinstalling the bulbs to check that they are seated correctly. Unplug the fitting and remove it from your aquarium. Unscrew the end caps before gently removing each bulb. Reinstall each bulb, screwing it carefully back into place, and then test.

If this doesn’t work, try installing a new bulb. This will inform you whether the problem is with your bulb or the electronics and wiring.

If only one bulb isn’t working, try switching the starter to the bulb that is working. (The starter should be visible without taking too much of the hood apart.) If this doesn’t work, the problem will likely be either the ballast or the bulb itself.

How Do I Change The Ballast In My Aquarium Light?

In a fluorescent light, the ballast regulates the current to the light, providing it with sufficient voltage. Without this regulation in place, the bulb will quickly draw excess energy. If you try replacing an old bulb with a new one that won’t light up, the ballast is your most likely culprit.

To change the ballast, follow the steps below:

  1. As with any electrical appliance, ensure the energy source is turned off and disconnected before you begin work.
  2. Disconnect and remove your light fixture from the tank.
  3. Remove the cover from the fixture.
    1. Some come away easily, while others have locking clasps on the side.
  4. Remove the light bulbs by screwing them 90 degrees and gently pulling until the bulb releases.
  5. Inspect the sockets holding the end of each bulb. 
    1. If these are loose, you may want to consider tightening or replacing them.
  6. Take the cover plate off the wires (often located in the fixture’s center).
    1. Now you should be able to see both the ballast and its wiring.
  7. Locate the black and white wires – these are the power source for the light. 
    1. Test each wire with a non-contact voltage tester to confirm there is no power to the device. 
  8. Unscrew the mourning bolts or nuts and remove the ballast from its fixture.
  9. Take the ballast to the local hardware so that you can find a suitable replacement.
  10. Once you have the new ballast, mount it to the fixture by screwing it into place with the nuts and bolts that you removed earlier.
  11. Reinstall the cover plate, light bulbs, and cover.
  12. Reconnect the fixture to a power source and mount it back into your aquarium.

It’s important to note that some fluorescent light ballasts (particularly older ones, i.e., made before 1979) are classified as environmental toxins because they contain PCBs (polychlorinated biphenyls. You need to treat these as hazardous waste and dispose of them in line with the recommendations of your local authority.

How Do You Change A Fluorescent Light In A Fish Tank?

Fluorescent bulbs are the most common type of lighting in aquarium tanks, so knowing how to change one is essential.

  1. Disconnect your energy source before you begin. Allow the bulb to cool for about 15 minutes before you start work.
  2. If your bulb is encased, remove the cover. And if it’s screwing into place, unscrew the brackets with a screwdriver. 
  3. Grab hold of the light bulb with both hands and remove it.
    1. The best way to remove the bulb is to twist it anti-clockwise as you gently pull it with your hands.
  4. Inspect the sockets that hold the end of each bulb.
  5. Place the new bulb into the socket and secure it by screwing it into place and replacing the cover.

As with the ballast, you need to dispose of fluorescent bulbs responsibly. Local regulations apply because the bulbs contain mercury.

Do LED Aquarium Lights Need To Be Replaced?

Low-quality can burn out or stop working long before they should. One way to combat this is by opting for LED lighting, which is much less likely to malfunction.

Many consider LED lights preferable to other bulbs as they possess greater energy efficiency and release less heat. That said, your LED light can still malfunction, causing problems for your fish and aquarium.

In general, an LED bulb should have a lifespan of around 50,000 hours, meaning it will likely last for approximately ten years. You will have to replace it eventually, though far less frequently than a fluorescent bulb.

Final Thoughts.

From loose connections to faulty starters or blown bulbs, there are many reasons why the hood light might not be working on your aquarium. Keeping a small toolkit and replacement bulbs on standby is a good idea that allows you to rectify any issues with lighting quickly.

In addition, knowing how to replace your starters and bulbs goes a long way in maintaining the optimum light for your tank.

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Erik Miller

Passionate scuba diver

Hello, there. Welcome to my blog. I am Erik and I’m the main editor of Sealife Planet website.

My passion and hobby has always been scuba diving. My mission is to grow this website and help others with useful information about the sea world. Enjoy! is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to

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