How high should aquarium lights be?
This is an important question because the height of your aquarium lights can affect how well or how poorly your aquarium plants or corals grow. Some aquarium areas will be poorly lit if the lights are set too low, and your plants will not grow well.
If your lights are too high, most of the light will be wasted, and your plants or corals will also not receive sufficient light to grow and thrive.
The optimal height for an aquarium light is not too low that it casts shadows and allows less light to reach the edges, and also not too high that wastes energy and deprives the aquatic plants or corals of the PAR they require to grow.
A step-by-step procedure that works for all types of lighting, including T5s and LEDs, is the preferred method for determining the optimal height. Follow the simple procedures outlined below to get the correct height for your specific configuration.
Steps to determine how high should aquarium lights be.
1.Darken the room where the aquarium is housed.
You are doing this to clearly see the “edge” of the aquarium light on the floor, and if the room is too bright, this would be impossible.
2.Raise the light to a height of at least 20 inches above the aquarium.
Take note of the “edge” of the light on the floor. Due to reflector or optical performance, it should be reasonably evident with most lights.
3.Lower the light gradually.
Do this until the light’s edge is captured within your tank and not on the floor. This will be the optimal height for the light.
This height will also maximize the amount of light that enters the aquarium, reflecting off the glass to reach under overhangs and outcroppings, especially when the glass is clean.
You can obtain increased PAR by lowering the light somewhat further; however, doing so reduces the amount of light reflecting off the aquarium’s wall, thereby decreasing the amount of light under overhangs and outcroppings.
What if some parts of the aquarium is still in the dark?
If you are using LED strip lighting and have a wide aquarium and there are still poorly lit parts, you can add a second light behind or in front of the existing light to ensure that the whole aquarium is illuminated.
These LED lights usually come with a bracket that neatly fits your aquarium and is already set at the correct height. Still, as the LEDs are in a strip format, they only illuminate a certain width of the aquarium.
