Reef Aquarium Lighting: Unleashing the Power of PAR and Spectrum

bright exotic anemonefish swimming in aquarium

Reef Aquarium Lighting: Understanding PAR and Spectrum


Creating a healthy and vibrant environment for corals in a reef aquarium requires more than just adding water and marine life.Lighting, often overlooked by beginners, plays a pivotal role in the overall health and vitality of the aquatic ecosystem. Understanding the concept of Photosynthetically Active Radiation (PAR) and light spectrum is crucial in setting up a thriving reef aquarium. As corals are photosynthetic organisms, the quality of light they receive directly impacts their health and growth.

EasternMarine Aquariums (EMA), a leading expert in saltwater aquarium setup, recognizes the critical importance of these factors. They provide an array of lighting options, each carefully designed to cater to the specific needs of various marine organisms. With the right balance of PAR and spectrum, it’s possible to create a lively, colorful reef aquarium that closely mimics the natural marine environment.

What is PAR and Spectrum in Reef Aquariums?

PAR, an acronym for Photosynthetically Active Radiation, measures the amount of light available for photosynthesis – the process that corals use to convert light energy into chemical energy for growth. On the other hand, the spectrum refers to the range of light wavelengths emitted by the aquarium lighting. Each color in the spectrum represents a different wavelength, with blue and red light being most beneficial for photosynthesis.

Together, PAR and spectrum play a significant role in the life of corals, providing the energy they need for growth, and influencing their vibrant colours. For example, zooxanthellae, the symbiotic algae living in corals, utilize specific light wavelengths for photosynthesis, which in turn supports coral growth and contributes to their bright coloration. EMA provides a vast selection of reef aquarium lighting options, each offering different PAR and spectrum characteristics to suit unique marine environments.

Types of Lighting and Spectrum Options for Reef Aquariums

There are numerous types of reef aquarium lighting, with LED lights being the popular choice due to their energy efficiency and control over intensity, photoperiod, and spectrum. LEDs allow for customization of the light spectrum, enabling reefers to provide the optimal light conditions for their corals. Certain LED fixtures are specifically designed for reef tanks, offering balanced light requirements for these unique aquatic ecosystems.

Brands like Red Sea ReefLED or EcoTech Marine Radion are trusted names in the industry, known for their quality LED products. For instance, the Radion provides a full-spectrum output with adjustable intensity, making it a great choice for a diverse range of corals. EMA stocks an extensive range of these high-quality products, providing reefers with a multitude of spectrum options to cater to their specific needs.

Choosing the Best Spectrum for Your Reef Tank

Corals are highly adapted to their natural environment, where blue light dominates due to the filtering effect of water on other wavelengths like yellow and red light. Therefore, replicated this condition in a reef tank often results in a thriving reef ecosystem. The color of light, often measured as correlated color temperature (CCT) in kelvin, is a crucial determinant of the light spectrum for your reef tank.

Choosing the best spectrum for your reef tank is not a one-size-fits-all solution. It requires a careful evaluation of the individual requirements of your marine life and diligent observation and adjustment of PAR/PPFD (Photosynthetic Photon Flux Density) levels as needed. For example, some corals require more blue light, while others might thrive under a more balanced spectrum. EMA offers personalized guidance to assist customers in choosing the appropriate spectrum, thereby ensuring their reef tanks flourish.

Impact of Spectrum on Coral Growth and Colouration

The impact of light spectrum on coral growth and coloration is fascinating. In the presence of the right light spectrum, reef lighting stimulates the production of chromoproteins, which result in vibrant colors in corals. These chromoproteins, when excited by certain light wavelengths, give corals their stunning, vivid coloration.

However, signs of excessive or insufficient light, such as color fading, reduced size, browning, and slow growth, can indicate the need for adjustments in lighting. For instance, if corals are exposed to too much intense light, they may become bleached or lose their color. On the other hand, lack of sufficient light can lead to slow or stunted growth. Maintaining appropriate photoperiods, the relative lengths of light and dark periods, is also crucial for optimal coral health and growth. EMA, with its range of products and services, assists customers in achieving the ideal spectrum and PAR levels for their corals, thus ensuring a vibrant and thriving reef tank.

Optimising Spectrum and PAR Levels in Your Reef Aquarium

To optimize the spectrum and PAR levels in a reef tank, reefers can use several strategies. These include intuitive estimation based on observation, seeking recommendations from experienced reefers, or using a PAR meter for precise readings.

Spectrographs and Chromaticity charts, tools that provide a visual representation of the light spectrum, can be used to evaluate the spectral quality of lights. These tools can help ensure that your lighting provides a balanced spectrum that closely mimics the natural marine environment. EMA’s expertise in optimizing spectrum and PAR levels can guide you in making the necessary adjustments to achieve optimal lighting conditions for your reef aquarium.

Coral TypePAR Level (PPFD)
Smaller Polyp Stony (SPS)270-600*+
Larger Polyp Stony (LPS)70-170
Soft Coral50 – 250*

*Acclimation to higher light levels must be done slowly.


In the realm of reef aquariums, understanding and effectively managing PAR and spectrum are indispensable for the health and vibrancy of corals. These factors, when correctly balanced, can transform your reef tank into a thriving, colorful underwater paradise. As you continue to explore and experiment with your reef aquarium lighting, remember that EMA is here to provide expert guidance and support. Visit EMA’s website at to explore their comprehensive range of reef aquarium products and services. Their expertise and high-quality products can help you create and maintain a stunning reef aquarium, providing your marine life with the best possible environment.