How Long Should Aquarium Lights Be On

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Fish lovers have been thrilled to welcome various species of fish into their homes for decades, resulting in them being among the most popular pets. Naturally, therefore, aquariums have continued to grow in demand, with people purchasing them in all sizes, price ranges, and designs. However, there is a lot to learn for people who are new to keeping fish. In addition, this hobby can be expensive, especially when it comes to keeping high-end fish. 

How Long Should Aquarium Lights Be On? 

An aquarium provides a habitat for a variety of plants and animals. These living things require sufficient light to be healthy and function properly. However, overexposure to light can have detrimental effects on the balance of your aquarium. For example, algae thrive on light, so your aquarium can become swamped with algae growth if you leave the lights on for too long. Experts suggest that the best time for aquarium lights to be on is between 10 and 12 hours a day. 

Since we can get busy with daily tasks, it is not unusual to lose track of time. Therefore, lightning units with integrated timers have become very handy for those with aquariums. Otherwise, it is good to establish a set routine for your aquarium. For example, turn the lights on when you leave for work and turn them off the minute you come home. However, if you notice an overgrowth of algae in your aquarium, you might want to rethink your timing. 

The lighting provides so much more than a pleasant viewing element when it comes to your aquarium. In fact, without sufficient lighting, your aquarium won’t be able to achieve a proper and healthy balance. Your aquarium’s lighting is also responsible for providing oxygen and energy so that your aquarium plants, bacteria, coral, and fish can enjoy good health. 

Although the amount of time that your aquarium’s light is essential, other factors also come into play. These factors should also be kept in mind: 

The measurement of light 

When you are on the lookout for good-quality aquarium lights, you should carefully look at the lights’ measurements. The measurements of light include: 

Photosynthetically Active Radiation (PAR) 

This element of light offers the perfect environment for beneficial algae and plant growth. 


The brightness of aquarium lights is displayed as lumens. Therefore, an aquarium light with higher lumens will be brighter. 


Not all aquarium lights shine the same lighting color. For example, an aquarium light with a low Kelvin count will have a yellower and warmer color. On the other hand, an aquarium light with a higher Kelvin count will have a whiter shade. 


The amount of energy that an aquarium light uses is measured by wattage. 

So what measurements of light are best for aquariums? Well, that depends on what you have in your tank. Here are the recommended measurements: 

For tanks with only plants

If you mainly have plants in your tank, choose a light with a Kelvin count of around 7000. Then, you can select PAR lights of up to 30 for plants that require low lighting and more than 80 for plants that prefer high lighting. 

For tanks that only have fish 

If your tank isn’t full of plants or animals, you can choose a lower Kelvin rating. Fish don’t require lighting with high Kelvin numbers. In fact, if your tank is in a location where it receives sunlight, it might be sufficient. In the middle of the day, natural sunlight offers light of up to 5500 Kelvin. 

For tanks with coral 

Coral requires lighting with PAR counts of more than 300 and less than 500 to thrive. 

How Long Should Aquarium Lights Be On

Lighting types 

Since aquariums are growing in popularity, there is a more fantastic range of lighting to choose from. These are the most recommended types of lighting: 

Fluorescent lighting 

This is the most purchased type of aquarium lighting. However, there are pros and cons to fluorescent lighting. The upside of fluorescent lighting is that it tends to be more affordable than other types of lighting. However, the downside is the light’s inability to shine emitted light downwards into the tank only. As a result, some of the light reflects upwards, making it inefficient. 

Light Emitting Diode (LED) 

These lights are quickly becoming more popular among those with aquariums who don’t mind spending more initially. Although these lights are more expensive than fluorescent lights, they are more cost-effective to run, and they offer a better environment for the living things in the tank. In addition, these lights have a much longer lifespan than fluorescent lights while keeping their quality entirely. 

T-5 HO bulbs 

These bulbs are also fluorescent bulbs, but they offer nearly double the amount of brightness than those of standard fluorescent bulbs. As a result, T-5 HO bulbs are ideal for bigger tanks. In addition, these bulbs offer adequate heat. However, this means that the temperature of the tanks needs to be carefully monitored. If the temperature increases too much, the bulbs should be switched off for a few hours. 

Although these types of lighting are all capable of creating the perfect environment for your aquarium plants and animals, choosing between them can be tricky. As a result, ask yourself these questions before purchasing: 

  1. What is my budget? 
  2. How long would I expect my lights to last? 
  3. What do I have in my tanks? 
  4. How large and deep is my tank? 
  5. Do I want to invest in a glass canopy? 

You might find it easier to choose what fits your budget and tank best by asking these questions. It is crucial to remember that selecting lights without a protective cover would mean the added expense of a glass canopy to prevent moisture damage. 


An aquarium can be a wonderful way to share your love of the ocean with those you love. However, it is a commitment that requires consideration of several aspects. By choosing good-quality lights, your aquarium can be an excellent environment for all your aquarium plants and animals. 

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