When it comes to reef lighting, not all LEDs are created equal. For healthy coral growth, vivid coloration, and long-term stability, reef aquarists must carefully consider three essential lighting factors: PAR (Photosynthetically Active Radiation), spectrum, and mounting height. Red Sea’s ReefLED lighting system simplifies this process with scientifically backed Reef-Spec performance, smart control via the ReefBeat app, and an optical design that ensures safe, even light distribution.
In this comprehensive guide, we’ll walk you through the PAR output, spectrum tuning, and mounting recommendations for each ReefLED model, helping you get the most out of your reef lighting setup.
What Is PAR and Why Does It Matter in Reef Tanks?
PAR, or Photosynthetically Active Radiation, refers to the range of light wavelengths (400–700nm) that corals and their symbiotic zooxanthellae use for photosynthesis. It’s not just about brightness—it’s about delivering the right intensity and spectrum of light that corals can absorb to produce energy and grow.
Different coral types have different PAR needs:
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SPS corals (e.g. Acropora, Montipora) thrive at 200–350 µmol/m²/s
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LPS corals (e.g. Euphyllia, Acanthastrea) prefer 100–200 µmol/m²/s
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Soft corals (e.g. Zoanthids, Mushrooms) do well with 50–150 µmol/m²/s
ReefLED Models and Their PAR Coverage
ReefLED 50
Ideal for nano tanks and smaller reef systems up to 50 x 50 cm.
At a mounting height of 20–22 cm above the water:
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Center PAR: ~150–180 µmol/m²/s
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Edge PAR: ~80–100 µmol/m²/s
Best for LPS, soft corals, and low-demand SPS in shallow tanks.
ReefLED 90
Designed for mid-sized reef tanks up to 60–80 cm wide.
At 20–25 cm mounting height:
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Center PAR: ~250–300 µmol/m²/s
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Edge PAR: ~120–160 µmol/m²/s
Perfect for mixed reef tanks with both LPS and SPS corals.
ReefLED 160S
Optimized for large reef systems and high PAR demand (up to 80 x 80 cm per unit).
At a mounting height of 21–24 cm:
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Center PAR: ~300–350+ µmol/m²/s
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Edge PAR: ~150–200 µmol/m²/s
Ideal for SPS-dominated tanks and deeper displays requiring stronger penetration.
Reef-Spec Spectrum Explained
ReefLED fixtures produce a Reef-Safe spectrum composed of:
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REEF-SPEC Blue (23,000 Kelvin) – A mix of blue and violet wavelengths ideal for photosynthesis and coral pigmentation
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8,000K White – Balances colour rendition and provides full-spectrum support
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UV (395nm) – Promotes coral fluorescence and immune response
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Moonlight (3W Channel) – Enables low-intensity viewing and nighttime coral activity
This spectral balance supports both visual appeal and biological function, encouraging intense coral colour, growth, and polyp extension while minimizing nuisance algae.
Mounting Height Recommendations
Proper mounting height ensures optimal PAR spread and minimal shadowing. Here’s what Red Sea recommends:
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ReefLED 50 – 18 to 22 cm above water level
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ReefLED 90 – 20 to 25 cm
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ReefLED 160S – 21 to 24 cm for uniform spread, or 26+ cm for larger coverage with reduced hotspotting
Mounting arms and hanging kits are available to achieve precise positioning. The included pivot and locking features allow for easy service and fixture alignment.
How to Position ReefLED Units for Uniform Coverage
When using multiple lights:
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Space ReefLED 90 units 45–60 cm apart center-to-center
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Space ReefLED 160S units 60–75 cm apart
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Overlap PAR zones slightly to avoid shadowed areas
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Use the ReefBeat app’s lighting preview tools to model coverage and adjust spacing accordingly
For peninsula or cube tanks, center-mounted fixtures work best. For long display tanks, multiple evenly spaced units ensure balanced PAR distribution across coral zones.
Using ReefBeat to Monitor and Adjust PAR Output
The ReefBeat app provides real-time control over spectrum intensity and lighting schedules. You can:
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Customize photoperiods with sunrise, daylight, sunset, and moonlight phases
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Adjust blue and white intensity to target specific PAR levels
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Use acclimation mode to gradually ramp up light for new corals
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Review PAR spread diagrams and recommended intensities by coral type
With ReefBeat, it’s easy to adapt your lighting to coral demands without sacrificing stability or safety.
Final Thoughts: Light Smarter, Grow Stronger
Red Sea ReefLED lights combine scientific spectrum tuning, powerful PAR delivery, and user-friendly mounting options, making them ideal for reef keepers who want more than just brightness—they want biology-driven performance.
Whether you’re starting with a ReefLED 50 or outfitting a full SPS system with multiple 160S units, understanding PAR, spectrum, and mounting is the key to unlocking your reef’s full potential.
