How to Pick the Best Planted Aquarium Light
We get asked a lot of questions about lighting. 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’ve ever looked at the lighting in a cozy coffee shop versus a sterile hospital, you know that “white” lights all vary in color temperature, which is measured in units of Kelvin (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.
It doesn’t really matter what color spectrum you use to grow aquarium plants. They can thrive in any Kelvin range. 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. Simply speaking, you can choose a light with just about any color spectrum as long as it’s not too blue (such as those used for raising 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 all depends on the kind of aquarium plant you wish to grow. Low light (or low intensity lights) are good for growing anubias and cryptocoryne, crypts, ferns and other non-demanding plants. Medium lights can be used for stem plants, and all other species, except 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.
Next, we need to ask the question “What is low light and high light?” This is measured by PAR (or Photosynthetically Active radiation). Most manufacturers do not publish their PAR numbers. This rating is affected by distance from the light source, tank height, interference from the aquarium lid and plant placement. 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.
As long as there is enough light intensity, you can grow plants with any kind of light. However, we recommend an LED light over fluorescent, compact fluorescent (CF) or other types of light. Most LED-based planted tank lights are now made from LEDs. They can provide high brightness and low power consumption, so they don’t need to be changed as often. Some LED aquarium lights can be dimmable to adjust the light intensity for use in different tanks with different 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. Shop lights, however, have a wider light spread as they are designed to light entire rooms. (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.
It depends on how large your tank is and how bright the light spreads, so you might need more lamps to properly grow plants in each part.
Which light is best for you?
Now that you know the basics of planted tank lighting, you know that the answer isn’t that simple. There are several questions you need to answer for yourself:
– What are you trying to accomplish? Do you want to start your own aquascaping business, grow plants for profit, or enter an international competition? What type of plants are you looking to grow and what level of light intensity do they need? What are the dimensions of your aquarium 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 on a light that is efficient at growing low-light plants, if this is your first time getting into planted tanks. If you have extra birthday money, it might be worth looking into the more expensive options. Higher quality lights last longer and are backed by extended warranties. 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.
For more information, check out our LED Aquarium Lighting Guide for concrete suggestions on which lights to get based on your aquarium size.