How Long To Leave Aquarium Lights on In a Planted Tank?

-- By Carol

Every aquarist knows that maintaining a healthy aquarium is not always an easy job.

From cleaning the tank to feeding your fish, you need to monitor and control everything.

However, one thing that many hobbyists often overlook is monitoring the aquarium lighting hours.

Aquarium lights do a lot more than just make your fish more visible and easy for you to admire.

In fact, it won’t be wrong to say that the lighting of the aquarium is one of the main factors that play an integral role in determining the overall health of the aquarium.

The amount of light that the aquarium receives every day affects everything in it from the health and comfort of your fish, and bacteria and algae growth, to the health and growth of your aquarium plants.

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Talking about aquarium plants, you probably already know that plants – whether they are on the ground or in an aquarium – require light to flourish.

Too much or too little light can easily damage your plants and even kill them over time.

This is especially true for aquarium plants that are generally dependent on artificial aquarium light.

Therefore, it is important to know for how long you should keep the lights on in your aquarium and set the lighting hours (like a planted tank lighting schedule) according to the needs of your planted tank.

Unfortunately, sometimes, it can be tricky to set the right number of lighting hours for an aquarium.

This is especially true if you are just starting out with planted aquariums.

No worries – if you are having a hard time figuring out the ideal lighting time for your tank, you’ve come to the right place.

Scroll down to learn all about aquarium lights and for how long you should keep them on in a planted aquarium.

Factors Affecting the Light Needs of an Aquarium

There are multiple factors that come to play when you are determining the amount of light that your aquarium requires every day.

Scroll down to learn about them.

Type of Aquarium Plant

This is perhaps the most important factor that you need to consider.

Plants require light for photosynthesis, which is the process through which they get their food.

To carry out this process, they require plenty of light.

Some plants may require as much as 12 hours of light every day to remain healthy and flourish in your aquarium.

However, keep in mind that every plant has distinct requirements.

The precise amount of light a plant requires in a day depends on its type and even its size.

When it comes to aquarium plants, there are three types of plants that every aquarist should know about.

Light Needs of Carpet Plants

As the name suggests, carpet plants are found at the bottom of the aquarium.

Generally, these plants cover the base of the aquarium like a carpet. These plants generally require medium to high light to survive at the bottom.

They are very demanding and you may have to keep the light on for 12 – 14 hours to ensure they remain in good health.

Some of the most popular carpet plants include the following:

Dwarf Baby Tears: This is a beautiful carpet plant that can flourish well even in small aquariums. However, even in small and rather shallow aquariums, this vibrant-colored plant requires a lot of light so make sure you keep the lights on for an adequate amount of time every day.
Lilaeopsis: This is another renowned carpet plant that flourishes well in medium to high light. If 12 -14 hours of light every day is too much for the fish in your aquarium but they still prefer light in a moderate amount, this is the perfect carpet plant for you. This is because it can grow in medium light while allowing your fish to live comfortably.

Light Needs of Mid-Ground Plants

Mid-ground plants are usually low-maintenance. Generally, they require a low to moderate amount of light.

8 hours of light every day should be enough for these plants to grow and flourish well in your aquarium.

The best part about these plants is that while they do not require a lot of maintenance, they will still look stunning in your aquarium.

Some of the most popular mid-ground plants include the following:

Green Tiger Lotus: This gorgeous plant doesn’t require much care. Under the right conditions, this plant is pretty self-sufficient. Its daily light requirement is neither too little nor too much.
Pygmy Chain Sword: How would you like to grow some grass in your aquarium? If the idea seems appealing, this is the plant for you as it resembles ordinary grass in appearance. They are beautiful and their aesthetic appeal makes them one of the most popular mid-ground plants. They require gentle light to remain healthy and grow comfortable in your aquarium.

Light Needs of Background Plants

Apart from adding to the aesthetic appeal of your aquarium, background plants are used for a number of other purposes like hiding tank equipment, providing fish with a comfortable place to hide, and even adding depth to the aquarium.

Background plants are easy to grow and care for but they do have certain light needs.

Some of the most popular background plants include the following:

Amazon Sword: This is an amazing background plant that requires low to medium light every day. This means it will flourish well in your tank even if you don’t invest in an expensive lighting system.
Pondweed: Like most other stem plants, pondweed also thrives best in high light environments. It may survive in medium light as well but since its growth depends on the amount of light receives every day, your pondweed is less likely to flourish well in low or medium light.

As we can see, there are different types of aquarium plants and each plant species has its own light requirements.

Therefore, it is important to take the time to learn about the specific requirements of aquarium plants before introducing them into your aquarium.

Ambient Room Lighting

Another important factor that you need to take into account is the ambient light in the room.

If you have an outdoor aquarium or it is set in a place that receives a lot of natural light, it is possible that the aquarium may not require any artificial light at all.

However, it is important to understand that ambient room light is indirect which means that it is better to have artificial light for your planted aquarium.

Nevertheless, the lighting requirements of an aquarium in a brightly lit room are considerably lowered.

In other words, an aquarium in a room with lots of ambient light will almost never need 8-12 hours of artificial light.

Leaving the lights on for a few hours every day should be enough.

Algae Growth

Light is a contributing factor when it comes to algae bloom in the aquarium. Too many algae can produce a number of problems in the aquarium.

Therefore, one way to determine if your light settings are correct is to determine the algae level in the aquarium.

If the algae level is higher than usual, you are probably letting the lights on for longer than required.

Also, keep in mind that sunlight creates more algae than artificial light.

This means if you have an outdoor aquarium or it is placed near a window or any other source of natural light, you are likely to experience a higher level of algae in the aquarium.

Type of Light

Finally, the type of light also plays an important role. It is essential to understand that there are different types of light options that you can opt for. Each approach has its own pros and cons.

Fluorescent bulbs are one option. T8 and T5 are the most common florescent blub options for aquariums.

While both these blubs provide enough light for aquarium plants to grow, T5 bulbs are highly recommended as they are more powerful than their counterparts.

Furthermore, T5 bulbs are a better option for densely populated planted tanks.

1 -2 bulbs are generally enough for a med-sized tank depending on the specific light needs of the plants

Another option is to opt for LED lighting. LED lights are equally powerful but they are generally more cost-effective.

They can usually last up to 5 years. However, you have to install more LED lights as compared to fluorescent bulbs.

Furthermore, LED lights are aesthetically appealing and provide beautiful lighting effects for your aquarium.

All these factors can help you determine the daily light requirements of your planted aquarium.

A helpful tip is to make sure you keep the lights off for the most part of the day in a newly planted aquarium.

This will keep a check on the algae growth and will help your plants get comfortable in the aquarium.

Keep in mind that while it may seem overwhelming in the beginning, determining just how long you need to keep your aquarium lights on is not all that difficult.

Sure, there’s a lot that you need to consider but once you get the hang of it, it will get easier and your plants will thrive in the aquarium.

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