Reef Lighting – The Basics

New England Aquaculture
Apr 25
3 min read

Lighting is one of the most critical—and often expensive—decisions when setting up a reef tank. The options can be overwhelming, but understanding the basics of each lighting type will help you make the best choice for your setup. Here's a breakdown of the three main categories: High-Intensity Discharge (HID), Fluorescent (T5HO), and LED, plus a look at hybrid systems that combine them.

High-Intensity Discharge (HID) Lighting

In reef keeping, HID typically refers to metal halide lighting, not the standard HID lamps used in outdoor or horticultural setups. These are powerful lights that offer deep penetration and a natural shimmer effect.

Types of metal halide bulbs:

Mogul base: Screw-in, elongated
HQI (double-ended): More compact and widely available

Key features:

Available color spectrum from 6500K (yellow-white) to 20,000K (blue)
Wattages range from 50W to 400W
Known for creating a shimmering, natural sunlight effect

However, this power comes at a cost—heat. Metal halide fixtures run hot and often require chillers to maintain stable water temperatures. For smaller or home reef tanks, this can complicate your system.

Best suited for: Large or commercial aquariums with built-in heat management and room for extra equipment like chillers

Fluorescent Lighting (T5HO)

Often overlooked, T5HO fluorescent lighting is a great option for many reef tanks when used and maintained properly. These bulbs offer even, diffuse lighting across the tank.

Why T5HO works:

Emits a uniform spread of light—no “spotlighting”
Supports a wide mix of color tubes, including actinic blues (420–450 nm) for coral health
Easy to control lighting effects by using separate timers for different tubes

Setup example:

A 40-gallon tank with soft and stony corals may thrive under 4–6 three-foot T5 tubes
SPS corals should be placed in the top 6–8 inches for best light intensity

Maintenance tip:

Replace bulbs every 4–6 months to ensure proper spectrum and intensity

Best suited for: Aquarists who want even tank lighting without the heat or complexity of metal halides.

LED Lighting

The most modern and versatile lighting solution, LEDs combine energy efficiency, minimal heat output, and advanced features. They’re available in two main formats: strips (lower output) and pendants (higher output).

Why LEDs are popular:

Energy efficient and long-lasting
Capable of producing shimmer effects similar to metal halides
Highly customizable via built-in programming (sunrise/sunset, moonlight, lightning effects)
Many models can be run standalone or networked with master/slave configurations

While initial cost is typically higher, the long-term savings from reduced energy use and no bulb replacement often justify the investment.

Best suited for: Reef keepers looking for total control, high performance, and a clean aesthetic.

Hybrid Lighting Systems

Sometimes, the best solution is a combination of lighting types. Hybrid systems offer flexibility by blending the strengths of metal halide, fluorescent, and LED lighting.

Examples of hybrid setups:

Metal halide + T5HO: Powerful output with wide light spread
LED + T5HO: Color control and shimmer with even coverage
All-in-one fixtures: Include halide, fluorescent, and LED elements for a comprehensive solution

Many hybrids use timers or controllers to create dynamic light cycles, including moonlight and sunrise simulations. These systems often deliver performance that rivals high-end LED setups—at the cost of increased complexity.

Best suited for: Larger tanks and experienced aquarists who want the best of multiple lighting styles.

Conclusion

Each lighting method has its place in reef keeping, but LED lighting is fast becoming the gold standard. It offers:

Long lifespan and low maintenance
High efficiency and customizable effects
Sleek design and modern control options

While hybrid systems still serve a purpose—especially in large tanks—the future of reef lighting is LED, with increasing affordability and DIY potential through platforms like Arduino and Raspberry Pi.

If you can make the initial investment, LEDs will provide years of high-quality, low-hassle lighting for your reef.

Get Expert Guidance with New England Aquaculture

Need help deciding on a filter type? New England Aquaculture offers Service and Consultation Plans to guide you in disease prevention, system design, and best practices. Contact us today to ensure the long-term success of your reef tank!