How to Pick the Best Planted Aquarium Light
It all depends on what light you choose for your planted aquarium. This is a common question we receive. Let’s discuss three lighting options and their implications for beginners to help you get started with your planted tank journey.
#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 reading light that gives everything a yellowish glow may have a rating of 2700K, whereas a cool white light with a bluish tint may 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. Because we don’t like to see aquarium lights that are too bright or too dim, it comes down to personal preference. Many hobbyists like to use a neutral white light around 5000 to 6500 K because it’s said to best simulate natural daylight. A light can be chosen with any color spectrum provided it’s not too bright (such as the ones used to grow saltwater corals).
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.
How bright should the light you use? It depends on the type of aquarium plants that you are trying to grow. Low lighting (or low-intensity light) is good for anubias, cryptocoryne or crypts, ferns, as well as other plants that are not demanding. Medium lights are good for stem plants and most other species except for demanding carpeting plants. High light can grow almost anything but requires carbon dioxide (CO2) injection to maintain a fast growth rate and minimize the risk of algae blooms. We recommend that you start with low-light plants because they are the most difficult and beginner-friendly of all the species.
The next question is: “What is considered low or high light?” Plant growing lights are often measured in 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 will require a stronger light source to illuminate the bottom of its tank, where the plants are growing. A shorter tank doesn’t.
You can use almost any type or brand of light to grow plants as long as you have enough light intensity, but we highly recommend getting an LED light – rather than fluorescent, compact fluorescent (CF), or other light technology. Because they are brighter and require less power, LEDs are the most popular choice for planted tank lights. You can also dim the lights to suit different tank PAR requirements.
The intensity of light can vary based on the location it is measured in an aquarium.
You should also consider the spread or dispersal of light. Most aquarium lights have a good 1-foot light spread directly below them, meaning that plants outside of that window won’t get as much light and potentially won’t 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. Some aquarium lights are better quality and have a 120-degree spread of light, so they cover more space than generic brands.
Depending on the size and spread of your light source, you might need several lamps to grow plants in every part of the aquarium.
Which light is right for you?
You now know the basics of plant tank lighting. But it is not that easy. You have many questions to answer.
What are your goals? Are you looking to grow your first aquascaping plants, make a profit from propagating plants, or participate in an international aquascaping contest? What types of plants would you like to grow? How much light intensity (or PAR) do they require? – What are the dimensions of the aquarium, and how many lights do you need to cover it? – How much money do you have to spend on lighting? Which light is the best for you?
It’s okay to choose a low-cost light source that can grow low-light plants if you’re just starting out with planted tanks. But if you have some birthday money saved up, it may be worth considering the higher priced options. These higher quality lights tend to last much longer and have extended warranties backed by the manufacturers. These lights also have useful features such as the ability to dimm the light intensity and high water resistance, which allows them to withstand 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.