How Long to Leave Aquarium Lights On Planted Tank?

tropical freshwater aquarium

Light is a crucial element when it comes to the health of plants and fish in an aquarium. But how much light is ideal? How long should you leave lights on? This article highlights the ins and outs of lighting an aquarium.

So, how long to leave aquarium lights on a planted tank? Experts recommend at least 8 hours of light. A newly planted aquarium requires not more than 6 hours to avoid algae growth.

Offering more than 8 hours of light is not only a recipe of algae but is also detrimental to the fish. Light facilitates photosynthesis which I return gives out oxygen which is beneficial to the fish. 

Want to learn more about lighting an aquarium? Well, read on for much-needed insight. As stated you should leave the lights on for eight hours daily. During this period the plant performs photosynthesis helping it convert water, sunlight, and carbon dioxide into starch. 

When you switch off the lights at night, the plants will burn the stored starch enabling them to grow. This is why it is essential to keep a day/night schedule. 

Recommended Aquarium Lights (links to Amazon):

  1. Finnex FugeRay Planted+ Aquarium LED Light Plus MoonlightsOpens in a new tab.
  2. NICREW ClassicLED Plus Planted Aquarium LightOpens in a new tab.
  3. Current USA Satellite Freshwater LED Plus Light for AquariumOpens in a new tab.

Can I Leave my Aquarium Light on 24/7?

No! Not only will this lead to algae growth, but it will kill the plants and fish. You see, fish require at least 8 hours of light, the same case applies to the plants.

As such, providing more than the recommended hours will interfere with the plants’ photosynthesis, resulting in withering which leads to the accumulation of toxins. On the other hand, 24 hours of light will interfere with the fish sleeping patterns causing them to become stressed.

Eventually, the immune system of the fish will weaken and ultimate death will not be an option. Buy a light with a timer to achieve the recommended hours.

Is it Better to Leave Aquarium Light On or Off?

Well, this depends on how long you’ll be away. If it’s during the night, it’s a good thing to leave the light off. For a short trip during the day, you can leave the lights off.

However, for long trips, we recommended putting a light on a timer. Why? This enables you to achieve a day/night pattern even when you are far. And as mentioned above you have to provide the plants at least eight hours of light.

So, whether you should leave the light on or off depends on how long you’ll be away. To mitigate this headache, just purchase lights with timers.

Can Aquarium Lights be Too Bright?

While some plants require high lighting, you should consider the fish in the aquarium. This is because fish does not thrive in too bright light.

That said, different plants require different lighting. An easy plant will require low lighting, the medium plant goes with medium lighting, while a difficult plant thrives in high lighting.

Besides tropical plant species and red-colored plants are known to require high lighting. So, before brightening up the tank, consider the plant and fish species. And don’t overlook the fact that bright light can cause an algae bloom. 

Should You Keep Aquarium Lights on at Night?

No. Plants and fish in a tank require darkness to thrive. Keep the lights off during the night to allow the plants to burn starch they have accumulated during the day. This enables them to grow. On the other hand, fish need darkness for optimum relaxation.  

Which Types of Light are Available?

There are two types of lights that you can choose from:

  • Fluorescent bulbs
  • LED lighting

Under the fluorescent bulbs, we have the T5 and T8 options. While both are ideal for aquariums, T5 is highly recommended, thanks to their light intensity. Besides they are essential for densely planted aquariums.

LED lighting systems are in fact the most preferred by most hobbyists. They are cost-effective, come in different colors, long-lasting, and bolster the aesthetic touch of the aquarium.

If you have a densely populated aquarium T5 is your best fit. Meanwhile, if you want an appealing tank, purchase LED lights.

Also Read: 10 Best Fish for 1 Gallon TankOpens in a new tab.

What Affects the Lighting Needs of an Aquarium?

While the species of the plant significantly affect the lighting if the aquarium, every hobbyist should also consider the following aspects.

Carpet plants

These are plants found at the bottom of the tank. They require high to medium light for them to thrive. Plus, they are light-demanding therefore can require more than eight hours of light. Some of the most common species include Lilaeopsis and Dwarfbaby Tears.

Mid-level plants

They thrive in medium to low light and are easy to maintain at the same time. Eight hours of light is ideal for them. Pygmy Chain Sword and Green Tiger Lotus are two of the most popular ones.

Background plants

Background plants are generally ideal for bolstering the aesthetic appeal of the aquarium.

Besides this, they provide a resting area for the fish and hide tank accessories from sight. Basically, they require low to medium light. Pondweed and Amazon Sword are a favorite for most hobbyists. 

Also Read: 12 Best Fish Tank Filters 2020Opens in a new tab.

Is Ambient Room Lighting Enough?

Well, if you have an outdoor aquarium, then the natural light that it receives during the day is enough. However, for an indoor fish tank in a dark room, you’ll require artificial light. 

Why? Because the natural light is indirect therefore might not be enough for the plants. That said, a brightly lit room will require a few hours of LED lighting. 

What Should be the Optimal Color Temperature of the Light?

The color of the light predominantly depends on how you want your aquarium to appear.

Also, different colors have different ratings. That is, not so bright colors have a rating of more than 5000k while warmer colors ratings fall below 5000k.

Most hobbyists prefer a daylight rating of 6500k. So, choosing between 6000k and 8000k will enable the plants to thrive while providing you aesthetic appeal. 

Planted Aquarium Lighting Guide

How can you ensure that your aquarium is well lit? Below, we look at some of the factors you need to consider.

Lumen per liter 

Lumen refers to the amount of light a lighting source produces. Most LED and fluorescent bulbs have lumen ratings on them. Plants require different lumens. 

  • Easy – 10-20
  • Medium – 20-40
  • Difficult – more than 40

The spread of the light

The light must reach every corner of the aquarium to ensure optimum plant growth. Therefore opt for two LED or T5 bulbs to reach shaded areas.

Alternatively, you can opt for an LED array that evenly distributes light and mitigates decorations from blocking light. Avoid using one bulb as it provides uneven light spread. 

Color spectrums 

Yes. The color of the light also affects plant photosynthesis. An LED with a blue/red spectrum is an ideal fit as it provides a mind-blowing color contrast that blends with aquarium decorations and plants.

Besides, the red color enables the optimum coloration of red-colored plants. The trick is to go for a color spectrum that will improve the look of the tank.

Also Read: How to Clean Aquarium Sand: A Definitive GuideOpens in a new tab.

Related Questions 

Are LED lights ideal for fish in a planted aquarium?

Yes. LED lights do not produce excess heat experienced when using fluorescent bulbs. Heat can cause increased stress levels in a fish and also affect the health of the plants. Besides, you can provide dim light using this type which mimics moonlight.

Which color light is ideal for a planted aquarium?

While white light is essential for photosynthesis and flaunting blue hues, blue light significantly shows off the green and red-colored plants hence providing an excellent color contrast. That said, you should try different colors to see which works best for your tank.

Final Say

Lighting your aquarium should not exceed eight hours for a healthy and vibrant aquarium.

Consider the light spread, lumen, and color spectrum before installing any light in your aquarium. And don’t forget to achieve that color contrast for an aesthetic appealing tank.

Saurabh Kumar

I am a passionate fish keeper, with years of experience. You will find some really useful tips and information on this blog about Freshwater Aquariums.

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