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Fluval Light Settings For No Algae

Fluval Light Settings For No Algae

If you’ve recently acquired a Fluval light in hopes of becoming a passionate plant aquarium growing hobbyist, then you’re on the right track to becoming the owner of an albeit small, but thriving live ecosystem.

Fluval lights are a great way to illuminate your aquarium and provide a much needed light source to your plants, especially ones in their early growth stages. However, with consistent use of your Fluval light, you may have also noticed some unwanted algae growth. If this seems to be the case then you must be wondering what the best Fluval light settings for no algae are.

Algae may grow rapidly in the presence of high intensity aquarium lights, this may especially be the case if these lights are kept on for long periods of time during the day. White light tends to accelerate algae growth the most with blue light falling in as a close second.

To know what setting on your Fluval light will work best for your aquarium, continue reading this article as we’ll cover this as well as what color lights in particular impact algae growth the most, whether LED lights are to blame for increased algae and what other options there are for you to opt into when deciding what’s best for your tank.

What’s the best Fluval light setting for no algae?

According to Fluval itself, usually, 8 hours of light should work the best for your aquarium. Exceeding 12 hours would be dangerous and guarantee accelerated algae growth.

Starting off with about 4 to 6 hours of lighting and then slowly going on to increase the duration and adjusting as necessary, is the recommended practice when it comes to using aquarium lighting. Furthermore, it is suggestible to keep the blue hue for your Fluval at a minimum when setting up your Fluval lighting.

Whether you’re using a freshwater tank or a marine aquarium, your tank capacity, type of plants, and plant density are all factors that you must consider before finalizing your Fluval light settings. With this many variables, a bit of trial and error alongside some general know-how of general lighting science should help you determine the best settings for your Fluval light.

To adjust both the intensity of your Fluval light and the range of colors refer to this handy video.

Does Blue Light Cause Algae?

As per formally conducted research, algae shows the most rapid growth rates under white light but blue light does also accelerate algae growth in comparison to red light. This is the case because blue light occurs at a higher frequency on the visible light spectrum. 

Exposing your aquarium to blue light can result in excessive algae growth especially in the case of freshwater tanks. However, the level of algae growth is also contingent upon both the intensity of light and the time duration for which your aquarium is exposed to the light. Having either of these be exceedingly high could cause algae to grow exponentially.

In short, blue light does cause algae to grow but the effects can be limited by controlling the intensity and duration of the light.

Does Red Light Cause Algae?

Deciding on the right spectral range when it comes to setting up your aquarium lighting, is of the utmost importance to ensure the sustained healthy growth of your aquatic plants.

We’ve previously discussed how keeping blue light at a lower intensity would be beneficial for your tank (seeing as it is most likely to propagate the growth of algae). However, considering how red light impacts algae growth, could help create the ideal lighting conditions for your plant aquarium.

Research has also shown that algae do grow under red light but not nearly at the rate at which it grows under white and blue light. However, if a marine aquarium is exposed to red light, you will observe faster algae growth. 

What Spectrum Of Light Promotes Algae Growth?

While both the growth and rate of growth of algae are dependent upon lighting conditions, owing to the fact that this plant relies on light to photosynthesize its food, conditions like whether your aquarium is a marine aquarium or a freshwater one also play a role in encouraging algae growth.

For freshwater aquariums, blue light supports rapid algae growth, whereas red light yields greater algae when it comes to a marine aquarium. In general, though, white light has been deemed to promote algae growth at the fastest rate when compared to both blue and red light. 

Do LED Lights Cause More Algae In An Aquarium?

Despite what some plant aquarium hobbyist opinions may have led you to believe about LED lighting particularly being a cause of algae growth, there is no evidence to suggest that LED tank lighting causes algae growth any more than any other kind of lighting.

Once again depending upon the duration your aquarium is exposed to LED lighting and the intensity of said lights, you may expect to see varying levels of algae growth. If left on for long periods of time and at a high intensity LED aquarium lights can cause algae if they are kept on for extended hours and have high intensity. 

The upside with LEDs, however, is that both the aforementioned issues are easy to combat. You can always alter the amount of time you keep your light on and also lower its intensity to create the optimum lighting conditions for your tank. They’re also available in a wide range of colors so you can avoid buying the white ones which tend to promote algae growth at a greater rate.


The way to go about achieving one aspect of the optimum environment for your aquatic plants is to create an ideal lighting situation, one which provides light to your plants with a suitable color composition (one not too white or blue), of an appropriate level of intensity for the right amount of time. 

Generally, Fluval LED lighting with the blue intensity turned down left on for an average of 8 hours at a moderate intensity should work out just fine for your aquarium but you must consider the type of plants under your care before deciding on the most appropriate lighting conditions. 

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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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