LED vs T5 Reef Lighting
🐠 The short version: both LED and T5 grow corals well — it’s a trade-off, not a winner. LED = efficient, controllable, shimmer, but needs good coverage (can spotlight). T5 = broad, even, shadow-free spread and lovely colour, but more energy and bulb replacement. Many reefers run a hybrid for the best of both. Whatever you pick, PAR and coverage matter more than the technology.
🔧 Match light levels to your corals with the coral placement, light & flow guide, and see the fundamentals in lighting, flow & PAR explained.
The honest framing
There’s no universally “best” reef light — LED and T5 are different tools with different trade-offs, and both grow every kind of coral when set up properly. What actually determines coral health is enough PAR, good even coverage, and gradual acclimation — not the badge on the fixture. Pick the technology whose trade-offs suit your tank, budget and how hands-on you want to be.
Side by side
| LED | T5 fluorescent | |
|---|---|---|
| Coverage | Point sources — needs good spread/lensing or it can spotlight and shadow | Broad, even, shadow-filling — its biggest strength |
| Colour / look | Highly tunable colour; shimmer effect | Excellent, even colour blend; no shimmer |
| Controllability | Dimming, timers, ramps, custom spectrum | Mostly on/off (per-bulb spectrum by bulb choice) |
| Energy use | More efficient, less heat | Uses more power, adds more heat |
| Ongoing cost/upkeep | Minimal — no bulbs to replace | Replace bulbs periodically (≈yearly, staggered) |
| Upfront cost | Often higher for a good unit | Fixtures often cheaper; bulbs are recurring |
| Coral growth | Grows all corals incl. SPS with enough PAR | Grows all corals; long loved for SPS colour |
When each shines
- Choose LED if you want efficiency, programmable ramps/spectrum, shimmer, and no bulb-replacement chore — just plan the coverage (spread/height) so you don’t spotlight corals.
- Choose T5 if you want broad, even, shadow-free light and superb colour, and don’t mind the extra energy and replacing bulbs on a schedule.
- Choose a hybrid (LED + T5 in one fixture) if you want the even spread and colour of T5 with the control, shimmer and efficiency of LED — the popular “best of both,” at a higher price.
(Metal halide is a third, older option — intense and proven for growth, but hot and power-hungry; most new builds choose LED, T5 or a hybrid.)
What matters more than the debate
- PAR to the coral. Softies and many LPS want less; SPS want more. Match light to zone with the placement guide.
- Coverage. A light that’s even across the tank beats a stronger one that spotlights.
- Acclimation. New corals — and a new light — need gradual ramp-up, or you’ll bleach corals regardless of LED vs T5.
- Stability. A consistent photoperiod beats chasing settings.
The honest takeaway
Don’t agonise over LED vs T5 — either will grow a beautiful reef. Decide by the trade-offs that matter to you (efficiency and control, or even coverage and colour), size the light to your tank and corals, get the coverage and PAR right, and acclimate gradually. That’s what grows corals — not the acronym.
Sources & further reading
- Coralkin — Reef lighting, flow & PAR explained — the fundamentals behind this comparison.
- Coralkin — Coral placement, light & flow guide — PAR targets per coral.
- Coralkin — Reef aquarium equipment — where lighting fits in the full kit.
- Reef lighting references (Bulk Reef Supply, Reef Builders) per our lighting guide.
Common questions
Is LED or T5 better for a reef tank?
Both grow corals well - it is a trade-off, not a winner. LEDs are efficient, controllable, and give shimmer but can spotlight and need careful spread; T5s give broad, even, shadow-free coverage and great colour but use more energy and need periodic bulb replacement. Many keepers run a hybrid to get the best of both.
Do LEDs grow corals as well as T5?
Yes - modern reef LEDs grow all corals including SPS when set up with enough intensity and good coverage. Early LEDs had a reputation for uneven coverage and coral "burning" from too much point-source intensity, but current units and sensible acclimation handle it. Coverage and PAR matter more than the technology.
Why do people run hybrid LED and T5 fixtures?
A hybrid combines the even, shadow-filling spread and colour of T5 bulbs with the controllability, shimmer and efficiency of LEDs. It is a popular "best of both" for mixed reefs, at the cost of a higher price and still needing to replace the T5 bulbs periodically.
How much PAR do corals need?
It depends on the coral - roughly lower light for many softies and LPS and higher light for SPS. Whatever the fixture, the honest step is to match PAR to the coral and acclimate new corals to your light gradually. A PAR reading matters far more than whether the light is LED or T5.
Do T5 bulbs need replacing?
Yes - T5 fluorescent bulbs lose useful output and shift colour over time and are typically replaced on a schedule (often around once a year, staggered). That is an ongoing cost and task LEDs largely avoid, which is part of the trade-off.