Fluval Light Settings For No Algae In The Tank

As a person with years of experience in fishkeeping, I’ve realized the hard way that a balanced setting of lighting is not just for aesthetics. It’s equally important for the growth and development of the fish and other aquatic pets. 

One of the most important things about the Fluval LED light setting is that it helps to prevent the unwanted growth of algae. Remember that incorrect light settings can cause algal bloom which is very harmful for aquatic plants and animals. 

Also, there’s no saying about how ugly it looks when algae infest in the aquarium. The good news is, in this article, I am going to explain about the Fluval light settings so there’s no algae in your tank ever. Doesn’t matter if you are a beginner in this or experienced, the information in this article is going to be helpful all the time.

So, without making any delay, let’s get started–

3 Basic Components Of Aquarium Lighting

It’s important to maintain a balance because it’s the key to getting the best result. You see, if there is too much light there definitely will be algae growth. Again, if the light is too little, it will make the fish behave abnormally, and the growth of aquatic plants will be hampered.

From understanding the basics of aquarium lighting one can make the tank look very appealing, maintain the good health of tank inhabitants, and also prevent the growth of harmful algae as well. There are 3 basic principles of aquarium lighting–

  • Light spectrum
  • Light intensity
  • Duration of lighting.

1. Light Spectrum 

The lights have various spectrums which have their own different uses. For example, the red and blue light spectrums help in photosynthesis of the aquatic plants. However, the algae also use the same red and blue light spectrums to grow. 

On the other hand, white light spectrums inhibit algae growth. This is why choosing the proper light spectrum is very important. 

2. Light Intensity

When it comes to light intensity it should be managed in a way that’s neither too high nor too low. Because high light intensity will cause both the aquatic plants and algae to grow faster and use up all the oxygen in the water leaving very little of it for the fish. 

But if it’s too low then the aquatic plants won’t be able to properly photosynthesize and they will start to rot and ruin the aquarium’s health. 

3. Duration Of Lighting

After matching the intensity of the lights according to your tank inhabitants’ needs, it’s time to set the duration for it. Normally, the duration of lights needs to mimic the normal day night circle. 

Keeping the Fluval lights on for about 8 to 10 hours everyday is considered as an ideal duration. However, sometimes the photoperiod needs to be adjusted to higher or lower because of the needs of the fish kept in the aquarium.

3 Reasons Why Do Algae Grow In The Aquarium 

Algae is something that every aquarium owner has to deal with at one point in his life. Sometimes a little growth of algae can be tolerated but too much growth can just rapidly get out of control and make the tank look very dirty and unhygienic.

The following reasons can cause the excess growth of algae–

1. Excessive Light

Algae thrive in high intensity light. So, if your tank is exposed to high intensity light or even for a longer duration, it can also cause a rapid growth of algae. This is why it’s very crucial to control the duration and intensity of light as well as the light spectrum. 

2. Imbalance Of Nutrient 

If the fish are overfed or the water isn’t changed regularly it can cause accumulation of different nutrients like ammonia and nitrite. As a result, the algae are provided with a boost of nutrients and they naturally outcompete the other aquatic plants and quickly take over the entire tank. 

3. Poor Tank Maintenance

Your aquarium needs regular maintenance of various things. Like changing 25% of the water every week, cleaning filters on a regular basis, etc. Overstocking of fish can also deteriorate the water quality very quickly and help the rapid growth of algae indirectly. 

Besides, you also have to maintain the water movement through the filter. Otherwise, organic matter will accumulate in some places due to low water movement. As a result, the nutrients will slowly break down and help in the growth of algae. 

Lastly, when all these reasons above work in combination then the growth of algae takes up an even more dangerous form threatening the very existence of our fish. 

3 Ways To Create The Best Fluval Light Settings For No Algae In The Tank

Well, the definition of a perfect light setting will not always be the same. It will greatly depend on the type of tank, aquatic plants, and most importantly what tank inhabitants you have. For example, some fish are nocturnal and they need a longer period of light than the normal around 12-14 hours. 

On the other hand, some species of cichlid require a shorter period of light (8-10 hours) to maintain their health. Besides, a tank with a  set of live aquatic plants will need more hours of Fluval LED lights than a tank with no live plants. 

So, that means you have to decide what is the ideal light situation in your tank based on what type of fish you have. This is why Fluval LED lights are very popular among aquarists because they are very adjustable and help to create the best environment for the fish and plants while making it algae free. 

Now, let’s check out what parameters are to be adjusted—

1. Adjust The Light Intensity

The light intensity shouldn’t be too high. Start with around 50% light intensity in your tank and observe if the aquarium is growing any algae. It’s also important that your aquarium inhabitants are taken into consideration when setting the light intensity. 

Because some fish prefer medium to slightly higher light intensity to maintain their health. While some other aquatic animals prefer lower light intensity. So, after getting a particular fish it’s better to research what kind of light intensity they like. 

More or less, it’s like creating a comfortable light setting for your fish and aquatic plants that also prevents the growth of algae.

2. Adjust The Light Spectrum

Fluval LED lights come in very handy because you can customize the color spectrum according to your liking. We already know that blue and red light spectrums are essential for the growth of aquatic plants. On the other hand, they also promote algae growth. 

This is why the light spectrum has to be chosen in a way that mimics the natural sunlight which is mostly green and yellow light spectrum. Feel free to experiment with the spectrum and keep adjusting based on the responses of your fish and plants in your aquarium.

3. Set The Light Duration

The light duration or photoperiod plays a great role in preventing the growth of unwanted algae. The best choice is to start by having 5-6  hours of light then increase gradually to 8-10 hours a day mimicking the normal day night circle. 

After that, you have to observe the tank situation and adjust based on the plant and fish performance. A good thing is that you don’t have to worry about turning the lights on and off. Because the Fluval LED lights already have a built-in timer so that you can set the duration and it will maintain the photoperiod cycle every day without needing your assistance.

Besides, these Fluval LED lights also come with a night mode which means they can provide a soft blue light during the night time mimicking the natural day night cycle. This will not only make the aquarium look aesthetic but also provide a stress free environment for the fish. 

Tips For More Effective Algae Control 

Sometimes adjusting the lights only will not control the growth of algae in your tank. There are some other things that make a huge impact on this situation. Check out the tips on how to take some additional measures to say goodbye to algae forever–

  • Doesn’t matter if your tank is either a freshwater or saltwater tank, you always have to make sure the tank is clean. Make sure to remove the floating uneaten foods and debris once every day.
  • Check your tank on a weekly basis for any visible algae growth and clean it up immediately if you find any.
  • Every week change around 25% of the tank water to help dilute the nitrite levels which cause the algae to grow.
  • You can get a UV sterilizer to kill off the algae with ultraviolet rays. It will also prevent the growth of algae making it a great tool for algae control.
  • Another thing is that algae love when nitrites and phosphates in the tank are high. This is why you have to carefully feed the fish without ending up overfeeding them in any case.
  • Try to put in that much food so that your fish can finish up within a few minutes.
  • Besides, it’s better to not overstock the tank with fish because an excess number of them will generate more fish waste and cause a high level of urea in the aquarium.
  • Keep some live plants in the aquarium so that they can outcompete the algae by consuming the resources of the tank. 
  • There are some fish species such as Amano shrimps, Otocinclus catfish, Siamese algae eaters, etc. that feed on algae and these can be added to the tank so that they can finish up any traces of algae in your tank.  

Frequently Asked Questions (FAQs)

What is the best color light to prevent algae?

Green and yellow light spectrum has proven to be the ones that prevent the growth of algae to some extent. In addition, the white light spectrum also inhibits their growth. To prevent their growth red and blue light spectrums should be kept under check.

What kind of light kills algae?

Ultraviolet light pierces through the algae cells, damages their DNA, and kills them. UV light is very effective against the algae that freely float in water. Besides, UV lights also control other harmful microorganisms such as parasites and bacteria from water.

Does reducing light reduce algae?

Since algae live by photosynthesis like any other plants, if you deprive them of light it will make sure they don’t get to survive. However, you cannot just totally turn off the lights of your aquarium. Because it will weaken your aquatic plants and fish as light is equally important to them too. Rather you have to control the light settings to prevent algae.


Having proper light settings in the aquarium is necessary because our fish and aquatic plants need enough hours of light to survive and thrive. But the light setting has to be controlled in a way that keeps the fish and plants comfortable while making it harder for the algae to live. 

The light settings will be different based on the type of tank, size of tank, type, and number of tank inhabitants and aquatic plants, etc. So, don’t be afraid to experiment and try different light settings to find out what works best for your tank. 

Once you find the right Fluval LED light settings for your aquarium you will be rewarded with healthy and delightful aquarium conditions with no algae at all. Share this article with your other aquarist friends and hit the comment button if you have anything to ask about the aquarium lighting.

Howard Parker

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