Aquarium light is the crucial element of your aquarium because you want to see your fish, and It provides light for your aquatic plants or corals to grow. You might be wondering if your aquarium light can be too bright and if it will cause problems in your aquarium?
Aquarium lights can be too bright. There are several disadvantages to having aquarium lights that are too bright, including algae growth as well as stressed fish.No more than two watts per gallon are recommended for a low-tech planted tank, and this will provide just enough light for thriving plant growth and minimize algae growth.
Disadvantages of too bright aquarium lights.
Algae growth
Excessive algae growth is one of the biggest reasons most fishkeepers will quit the Hobby, and excessive light is the main culprit that will produce algae growth in most aquariums.
There are many different types of algae, which too bright aquarium lights can cause. Simply by reducing the intensity of the light, the algae growth can be reduced or eliminated.
In a non- CO2 planted aquarium, the general rule is not to exceed 2 Watts per gallon of the aquarium lights. By not exceeding this brightness, you will not stimulate excessive algae growth, and you will also get some nice growth for your plants. It is generally better to have lower brightness for a longer photoperiod than excessive brightness for a shorter photoperiod (duration of time)
For example, it is better to have a 2 Watts per gallon light on for 10 hours than a 4 Watts per gallon light on for 8 hours. The brighter light will most certainly cause algae growth, while the less bright light will provide the right balance to give you plant growth without the algae growth.
Stressed fish
Some types of fish don’t like bright light, and because of this, they will be stressed and will be hiding most of the time and not showing their normal behavior.
You can solve this problem by adding floating plants in your aquarium to provide shaded areas for your fish to get away from the bright light.
How bright should aquarium lights be?
Depending on the type of aquarium you have and the type of aquatic plants you wish to grow, you can have different aquarium lights.
If you have a normal low-tech planted tank, then the rule of 2 Watts per gallon will apply.
If you have a high-tech CO2 injector tank, you can ramp up the brightness of the light quite a lot, and then you will also be able to grow plants that are considered advanced and quite difficult to grow in a normal aquarium.
Tropica aquarium plants group their plants as easy medium and advanced, and for each type of plant that has a different recommendation of the brightness of light that is required
In the table below, you can see the different recommendations:
| “Easy” plants | 10-20 lumen (0.25 to 0.5 watts) per liter. ( 1 to 2 watts per gallon) |
| Medium” plants | 20-40 lumen (0.5 to 1 watts) per liter. ( 2 to 4 watts per gallon) |
| Advanced” plants | more than 40 lumens (1 watt) per liter. (more than 4 watts per gallon) |
We will advise that most non-CO2 injected aquariums will do fine with the first category of easy plants and less than 2 Watts per gallon of aquarium lighting.
Once you add CO2 injection to the aquarium, you can move to the more advanced medium and advanced plants, and then you can add more brightness to your aquarium lights.
Is bright light bad for fish?
Bright light will not harm fish, but some fish will be stressed by bright light and not show normal behavior. As mentioned before, you can solve all these problems by adding floating plants that will provide shaded areas in the aquarium.
Can you have too much light in a planted tank?
You can have too much light in a planted tank, which will cause excessive algae growth and stressed fish. By reducing the intensity of the light, you can reduce the algae growth and have happy fish.
