Do LED Lights Cause Algae Growth in Aquarium?

LED lights have quickly overtaken other kinds of aquarium lights in popularity because they have a longer life than fluorescent and metal halides.

Besides their longer life, they also consume less energy, have several different color options, and do not heat up your tank’s water as much as other aquarium lights.

Contrary to what you may have been told, LED lights do not cause algae growth any more than other aquarium lighting options. Some LED lights also have adjustable light options to dim or brighten the light according to your fish’s needs.

This means that fish are also more comfortable with LEDs because, according to their preferences, they can have a dim light without having to shut the light off—which makes it easier for you to keep an eye on your fish.

This also discourages algae growth more than anything else—because it’s not the kind of light that causes algae growth, but the intensity of it.

Here are some other things you need to know about algae and LED lights before you decide which tank light will work best for you.

Do LED Lights Cause Algae Growth in Aquarium?

As we’ve mentioned before, algae growth doesn’t depend on what kind of light you’re using. In fact, some fish owners will say that LED lights are the least likely to encourage algae growth.

What really causes an algae outbreak in your tank is the intensity of the light, as well as how many hours in the day you keep the light switched on.

If you have your aquarium lights on for 8 to 12 hours a day, there is a high chance that you’ll encourage algae growth. This applies across the board: Whether you use metal halide, LED, or fluorescent lights.

An interesting aspect of LED lights is that they have a lower intensity than other lights. They’re also not full spectrum.

Full-spectrum lights try to resemble daylight—and the longer you have them on, the more likely it is for algae to break out.

LED lights can be modified to give off a duller light. You can even get a dimmer color, such as blue, to reduce the chances that a white LED light may have of causing algae (even though they are already very slim).

If you opt for a 30w LED light, it will have a much smaller chance of causing LED than, say, a fluorescent light because fluorescent lights don’t have the option of higher and lower intensities.

Additionally, fluorescent lights degrade over time, and if you have a larger tank, you may notice that an area where the light is newer has traces of algae growth whereas the areas where the light has begun to dim wouldn’t.

What Causes Algae Growth?

Algae growth is caused by a mixture of CO2, light, water, and fertilizer. Whenever there is too much of any of the four, it can lead to algae. It’s obviously not possible to limit the amount of water in your tank, nor can you reduce the nutrients that you use to feed the fish.

However, you do have the light intensity in your control.

Keeping the light on for too long, setting up your aquarium by a window where there is constant exposure to sunlight, or having lights that are extremely bright all-cause algae growth.

You can avoid putting too much feed in the tank—if your fish have a tendency to leave some pellets—they’ll eventually be used to promote algae. Along with avoiding overfeeding, make sure you clean your tank as often as it is required. A dirty tank leaves excess matter that algae can use to grow.

Are LED Lights Suitable for Aquarium Plants?

If you have live aquarium plants in your tank, you might want to opt for lights that create a suitable environment for them to thrive. In this case, LED lights may not be a preferable option.

They are not ideal for plants that require high-intensity light exposure. However, if you opt for a plant that thrives in a darker environment, LEDs are a smart choice.

What Can You Do to Prevent Algae Growth?

Keeping in mind the factors that promote algae, you can do the following to limit an algae outbreak in your tank.

Have Dimmer Lighting

You can either opt for lighting that is less intense or reduce the number of bulbs in your tank. Keep your tank in a spot where there isn’t constant exposure to sunlight.

This heats up your tank and promotes algae growth better than any artificial light.

You also need to thoroughly research which fish need different light intensities to thrive. For example, deep seawater fish prefer a dark tank environment, while there are fish that will become agitated if the lights are ever off.

Some fish need longer daylight hours than others—so depending on what breed you have, you can decide which kind of lights to opt for and how long you should keep them on.

Ideally, an aquarium light should not be on for more than 10 hours and 12 hours at the max. In case you forget to turn off the light, set an alarm.

Don’t Overfeed Fish

We have a tendency to throw too much fish food into the tank without measuring out how much our fish actually need.

Depending on how many fish you have and the size of your tank, most fish are usually done with their feeding in around 5 minutes.

If you notice that there is still food floating around after 5 minutes, you’re throwing in too much food. Use a net to scoop out the excess food to prevent it from getting lodged in the filter or promoting algae growth.

Keep Live Plants

Live plants have a tendency to absorb the excess nutrients in the water. Even if you forget to clean out the food, live plants can help you take care of the excess.

However, if your aquarium is bursting with excess nutrients, a few plants are not going to prevent an algae outbreak.

Get Fish that Eat Algae

Another option is to invest in fish that scour your tank and eat all the guck.

These kinds of fish include Bristlenose plecos, Siamese algae eaters, Otocinclus catfish, Twig catfish, Amano shrimp, Nerite snails, and Chinese algae eaters, among others.

Do some research before purchasing a new fish to ensure that it will get along with your other fish and thrive in the environment you have created.

Some of these algae eaters only survive in freshwater aquariums, while others do not.

Get a Good Filter

Another way of ensuring that your tank’s water stays clean and to avoid a surplus of nutrients and phosphates is to get an effective filter. A strong filter can remove iron, nutrients, nitrates, and other elements which algae feed off of.

Using tap water increases the chances of excess contaminants in your water and can put pressure on your filter, so if you must use tap water, try to filter it out before pouring it into the tank.

To test the water for contaminants and phosphates, run a test. If there are high levels of iron and nutrients, you’ll have a harder time avoiding algae, despite a strong filter.

Keep Your Tank Water Clean

If your tank is dirty, there are more contaminants in the water for algae to feed off of.

You should ideally clean your tank every three to four weeks at max, more so if you have fish that create more pollution and require a stronger filter.

Not only is dirty tank water harmful to your fish’s wellbeing, but it also promotes all sorts of unwanted growth. It can reduce a fish’s life expectancy and spread disease throughout the tank.

If you can—clean out at least ¼ of your tank’s water and exchange it for clean water.

When you do notice algae, give your tank a good scrub and clean away the growth.

If you catch it before it has spread, you can do a lot of damage control by just wiping down the affected area with a sponge or scraper.

It doesn’t ensure that the algae won’t return—since your tank’s environment won’t change—but it will get rid of the algae for the time being.

Final Words

Don’t feel put off if you find algae in your fish tank. It doesn’t necessarily mean that you aren’t doing an acceptable job of maintaining the tank.

In fact, it just means that there are too many nutrients—which means that your fish are well-fed and thriving.

LED lights don’t encourage algae growth any more than other lights, so as long as you keep a careful watch of how long you leave your lights on and what their intensity is, it should not make much of a difference in which kinds of lights you opt for.

However, if you’re interested in lights that have modifiable intensities, colors, and do not consume as much energy as their counterparts, then LED lights may be a viable option for you.

Make sure you check to see what light intensity is optimal for your fish’s habitat.

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