How to Pick the Best Planted Aquarium Light
The most frequently asked question is, “What kind of light should I use for my planted aquarium?”. Let’s take a look at three lighting parameters that can be used to start your journey with a planted tank.
#1 Color Spectrum
If you have ever compared the lighting in a coffee shop to a hospital, you will know that white lights can vary in their color temperature. These are measured in Kelvins (K). A soft, warm light that gives everything a yellowish glow could have a rating at 2700K. On the other hand, a cool, white light with a blueish tint might be labeled as 10,000K.
To be honest, color spectrum doesn’t matter that much when it comes to growing aquarium plants because they can thrive under a wide range of Kelvin. It mostly comes down to human preference because we don’t want to look at aquarium lights that are too red or blue. Many hobbyists like to use a neutral white light around 5000 to 6500 K because it’s said to best simulate natural daylight. As long as the light isn’t too blue (like those used to grow saltwater corals), you can choose from any color spectrum.
Plants can grow under a wide spectrum of lights, so pick a color temperature that you feel makes your plants and fish look the best.
Light Intensity
How bright of a light should you get? First off, it depends on what kind of aquarium plants you want to grow. Low-intensity or low-intensity lighting can be used to grow anubias (or cryptocoryne), ferns and other plants that are not demanding. Medium lighting is best for stem plants, and all other species, except carpeting plants. High-lights can grow nearly anything but require CO2 injection to keep up with fast plant growth. We recommend that people start by growing low light plants, as they are the easiest and most beginner-friendly to grow, due to the complexity of high-light planted aquariums.
Next is the question: What is considered low light or high? The intensity of plant-growing lights is commonly measured as PAR (or photosynthetically active radiation). Manufacturers don’t publish PAR numbers as they are affected by the location of plants, distance from light source, aquarium lid interference, and the height of the tank. A tall tank requires a stronger light to illuminate the bottom of the tank where the plants are growing, whereas a short tank does not.
Any type of light can be used to grow plants, as long as it has enough intensity. But we strongly recommend that you get an LED light, rather than a compact fluorescent (CF) light or another light technology. The majority of planted tank lighting uses LEDs today because they produce high brightness with low power consumption and do not need replacing as often. Many LED aquarium lights can also be dimmable so you can control the light intensity if you have different tanks.
The intensity of light can vary based on the location it is measured in an aquarium.
Light Spread
Last, you need to think about how the light spreads. Aquarium lights usually have a 1-foot spread of light directly below them. This means that plants beyond that window won’t get as much sunlight and may not grow as well. On the other hand, a shop light has a huge light spread because it’s designed to light an entire room. (Just be aware that the color spectrum on a shop light may not show off the colors on your plants and fish as well.) If your aquarium is between 18 and 24 inches in width, you might need two aquarium lights, or one shop light. There are some aquarium lights with a 120 degree light spread that are made by better manufacturers. These lights will cover a larger area than a generic brand.
It depends on how large your aquarium is and the spread of the light. You may need multiple lamps to properly grow your plants in every area of the tank.
Which Light is Right for You?
Now that you have an understanding of the basics behind planted tank lighting, it’s clear that there is more to the story. There are many questions that you will need to answer.
What are you trying accomplish? Do you want to start your own aquascaping business, grow plants for profit, or enter an international competition? – What kinds of plants do your want to grow? And what amount of PAR or light intensity are they looking for? What are the aquarium’s dimensions and how many lights will you need? – What are your financial limits and what light is most cost-effective?
You don’t have to spend a lot of money to get started with planted tanks. It may be worthwhile to consider the more expensive options if you have some spare money. The higher quality lights are more durable and come with extended warranties. They have helpful features like dimming the light intensity, and high water resistance to resist accidental drops in water.
Check out our LED Aquarium Lighting Manual for more information and concrete suggestions on what lights you should get based upon your aquarium’s size.