January 23, 2022

Beam Angle Selection Guide

Beam Angle Selection Guide

Why Do Beam Angles Matter?

We offer five beam angles to help you deliver the maximum amount of light to your aquarium. Because varied beam angles are usually only seen in large custom installations or public aquariums most aquarists are unfamiliar with this option.

By selecting an appropriate beam angle you can ensure that the light from your fixture is evenly spread from the front to the back of your aquarium and from edge to edge at the substrate level. Put another way, you don’t want a beam angle that is so wide that light falls outside the footprint of the aquarium. And most aquarists (the exception is explained below) don’t want a beam angle that is so narrow it “misses” the edges of the tank at the substrate level.

This is important in both freshwater and saltwater tanks where a consistent level of light across the substrate eliminates concerns about “hot spots” or areas where light levels (PAR) are low and plant life may be deprived of light. In addition, by focusing the light on the area where it is needed you maximize the efficiency and energy use of your already efficient LEDs!

Most freshwater aquarists will need a 75 degree or 90-degree fixture because we tend to place our fixtures close to the waterline. In addition, we don’t usually highlight a particular area of a tank. For this reason, the rest of this article is primarily written for those of us who keep reef tanks (or those who have non-standard aquariums).

Note: When viewed from the front our fixtures are designed to project light slightly outwards from each end to give you flexibility in arranging your lights. For example, a three-foot-long fixture can be centered above a four-foot-long tank and raised or lowered as needed to provide light coverage at the substrate level on either end.

The Exception

Some aquarists need to focus additional light on certain areas of their tanks—something you are most likely to see in a custom-built aquarium or when corals with specific light needs are being grown or where clams are kept. In saltwater tanks, one or more fixtures are sometimes installed with narrow beam angles focused on an area of the tank containing corals that require higher PAR readings (ie: more light) than the other residents of the tank while fixtures with wider angles are focussed more generally on the tank. In addition, some aquarists may wish to highlight a particular part of the tank or a particular species for aesthetic reasons. Build My LED allows you to select five different beam angles to deliver the maximum amount of light in any aquarium design.

Recommended Beam Angles

To achieve the highest light (PAR) levels in an aquarium with a single fixture (or a row of fixtures), we recommend the 75 or 90-degree beam angle mounted 2-3″ above the water. Select the 75-degree beam angle on tanks measuring up to 12″ wide (from front to back) and a 90-degree beam for tank widths over 12″. When mounting at this height (2-3″ above the waterline) the 60, 45 and 30-degree beam angles should only be used on aquariums with multiple rows of lights or to “target” a particular area when used with an existing lighting system.

Beam Angle Reference Guide

Approximate distance above the waterline

  • 2-3″ (I.E: Tank or Rim Mount)
  • 6″
  • 12″
  • 24″
  • Above 24″
Select this beam angle

  • 90 degree
  • 75 degree
  • 60 degree
  • 45 degree
  • 30 degree

Do you have an unusually shaped tank or non-standard light requirements? Please use this forum link to request information on other heights or configurations from our lighting design team.

Beam Angle Reference Examples

beam tanks
Photo shows a 90-degree beam angle from the side of the aquarium.
Left: Mounted 2.5″ Above Water. Right: Mounted 12″ Above Water

90 Degree Beam Angle

The 90-degree beam angle is the most popular beam angle for aquarium applications when the lights are mounted on the aquarium. When installed 2 to 3″ above the water, this beam angle is typically used to cover an 18″ wide aquarium.
Note: For aquariums with a single row of fixtures, this is usually the best beam angle selection when the lights are installed 2 to 3″ above the water.

75 Degree Beam Angle

The 75-degree beam angle is a very popular beam angle for aquarium applications. When mounted 2 to 3″ above the water, this beam angle is typically used to cover a 12″ wide aquarium. The 75-degree beam angle will cover an 18″ wide area when the fixture is installed at a 6″ mounting height.

60 Degree Beam Angle

The 60-degree beam angle will cover a 12″ wide area when the fixture is installed at a 12″ mounting height.

45 Degree Beam Angle

Like the 30 degrees, the 45-degree beam angle is typically used to deliver maximum PAR values in deep tanks. This beam angle is also used to maximize the amount of light entering a tank from elevated fixture mounting heights. Note: Due to the narrow beam, this beam should be used by advanced aquarists in technical applications.

30 Degree Beam Angle

The fixture above has a narrow 30-degree beam that has been “aimed” at a central area. The beam is tightly focused. Note: Due to the narrow beam, this beam should be used by advanced aquarists in technical applications.

2 thoughts on “Beam Angle Selection Guide

  1. Hi guys! i cant find any other way to get in contact. I got awesome lights a few years back for my saltwater set up. I know you don do saltwater anymore but i am having issue with one of my lights and i want to see if you guys can help me out with it?

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