Reef Lighting 101: Choosing an LED That Actually Grows Coral

June 08, 2026 · Maren Marine

Light is food for coral. Get it right and colors pop and growth takes off; get it wrong and even hardy corals sulk. The good news: you don't need to become a lighting engineer. You need three ideas and the right-sized fixture.

The three things that matter

1. Intensity (PAR). PAR is the amount of usable light reaching the coral. Soft corals and LPS are happy in the 75–150 range; SPS want more, roughly 200–350+. Too little and coral browns out; too much and it bleaches. Most modern LEDs are plenty bright — the trick is dialing them in, not buying the brightest box.

2. Spectrum. Reef coral loves heavy blue. A good reef LED is blue-dominant with enough white to look natural to your eye. This is also why coral looks electric under reef light — those blues make the pigments fluoresce.

3. Coverage. One light only grows what it actually reaches. A rough guide: one quality puck-style LED covers about a 24" × 24" footprint. Longer tanks need two (or a linear fixture). Skimp on coverage and you get a bright spot in the middle and shadowed corners.

The honest sizing ruleMatch the fixture to your tank's footprint and depth, not its gallons. A shallow 24" cube and a deep 24" cube need different intensity to push light to the sandbed. When a light lists a coverage area, treat it as the max for soft coral — shrink it ~25% for SPS.

What to buy, by tank

Nano & first reef

AI Prime 16HD Reef · $270
The default first reef light for good reason — full spectrum, app control, grows coral on tanks up to ~24" and looks great doing it.

Reef Breeders Photon V2+ · $375
Outstanding coverage per dollar for larger or budget builds — a lot of usable light without the flagship price.

Mixed reef

Kessil A360X / A500 · $520
That signature Kessil shimmer and color rendering. Point-source light reefers love over a feature rock or frag tank.

AI Hydra 64HD · $540
More pucks, more coverage, more power for a full mixed reef — schedule and tune every channel from the app.

SPS & showpiece

EcoTech Radion XR30 G6 · $700
The benchmark high-output reef LED. Six channels you actually control and the intensity to drive SPS color and growth.

Orphek Atlantik iCon · $1,200
Top-shelf coverage and spectrum for serious SPS systems where you want one fixture to do everything.

Straight talk — More light is not better light. New reefers routinely run fixtures too hot and bleach their corals, then blame the tank. Start your light around 50–60% intensity, acclimate over weeks, and let the coral tell you when it wants more.

Reefer's tip — Run a sunrise/sunset ramp instead of slamming the lights on and off. It's gentler on coral and fish — and a slow blue-heavy "dusk" hour shows off fluorescence beautifully.

See every fixture in Lighting, or let the Build Studio match a light to your tank's footprint and the corals you want to keep.

Tell us your tank size and whether you're after soft coral or SPS — the Build Studio picks a light with the right intensity and coverage for the job.

Open the Build Studio →

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