Reef Aquarium Lighting Guide

One of the most critical concerns when planning a new aquarium or modifying your lighting setup is how to properly light a reef tank. If you’re shopping for lighting solutions online, there’s a lot of data to sort through. The physics of light and corals is complicated and can be perplexing, especially when you’re searching for simple answers.

Reef lighting is without a doubt at the top of the priority list. What kind of lighting do I need for excellent coral growth? is a question we get a lot. Which lighting fixture is best for my aquarium? Although these queries may have an easy answer. It’s also crucial to comprehend the science that behind these decisions. Everyone knows how important light is for keeping SPS and LPS corals alive.

Many new reefers, on the other hand, have a habit of bombarding the corals with as much light as possible. Which shows that caged coral isn’t great. Aquarists used to buy the biggest, brightest light they could find in the early days of reef keeping. Coral reefs known to thrive under direct sunshine. As a result, DIY reefers attempted to harness the power of 100 suns to power their tanks.

Why not try it at home? That’s what the public aquariums were doing, so why not? It didn’t always work, though.

The light caused the water to overheat, causing some corals to stop growing and others to be scorched. More was not always better when it came to light. We now know a lot more about corals and other photosynthetic invertebrates’ illumination requirements. We tried to condense all of this information for you to make choosing a light easier.

Wireless controllability, programming options, and a stylish design are all important considerations when shopping for a light.

However, the PAR of the light, which is the first thing you should look at, is the king of all these parameters. Photosynthetic active radiation (PAR) is the abbreviation for photosynthetic active radiation. It’s the wavelength range that symbiotic algae residing inside coral tissue employ. Photosynthesis is powered by PAR, and photosynthesis is what feeds our corals. You’re wasting electricity if your lighting rig is bright yet doesn’t deliver the correct light spectrum.

Intensity is beaten by quality. PAR is find across the visible lighting spectrum, but is particularly strong in the blue (400–500 nanometers) and red (600–700 nanometers) wavelengths.

It is conceivable for a light to be bright but still failing to produce PAR. PAR measured in micromole photons per square meter per second (micromole photons per square meter per second). Fortunately, calculating a fixture’s PAR rating does not need any arithmetic.

The majority of today’s top LED light manufacturers publish PAR specifications for their fixtures, which makes life much easier. A PAR meter used to obtain these measurements.


The sensor initially submerged in water and illuminated. After then, readings taken at various depths and distances from the LED array’s center. The PAR readings then plotted to show how the PAR intensity decreases as you move away from the light.

You can use the PAR data provided by the manufacturer to estimate how much light your tank will receive with a given light fixture. You can also use a PAR meter to take your own measurements. PAR meters are a little on the expensive side. They do, however, allow you to see the PAR levels in your reef tank at various levels. It’s quite useful for selecting the ideal location for your corals or making minimal alterations. So, how much PAR should you give your corals?

PAR measurements taken by marine researchers on tropical reefs where SPS and LPS corals grow.

The PAR levels on the world’s reefs range from roughly 150 to over 450. But at what level will corals in a home aquarium be happiest? Dana Riddle, a captive coral researcher, revealed that the best average PAR range for corals is between 100 and 200 PAR. Overabundance of PAR is useless and actually slows photosynthesis, potentially harming corals. When using 200 to 400 PAR, brilliant coloration achieved at the expense of some coral growth.

Corals may even create brighter pigments to protect themselves from too much light, according to research. The main message is that captive corals thrive at moderate light levels.

The corals will be harmed or inhibited if there is too much light. There is no definite rule for the ideal PAR for all corals, but 150 to 250 PAR is a reasonable starting point. So, how do you pick the best light fixture for your aquarium?

Take a look at the PAR specifications first. They’ll give you an idea of how much PAR you can get at certain depths. There’s also no harm in going with a more powerful lamp as long as you can turn it down, which is especially useful when your corals adjust to a new lighting arrangement. If you can’t locate PAR statistics for a light, look it up online to see how other aquarists are utilizing it. It is always beneficial and valuable to learn from the experiences of others.