T5 reef lighting makes it easier to get results and are often much cheaper. It is not that T5s are inherently better than LEDs. In fact, it is possible to achieve even better results with LEDs but is it worth the necessary effort and expense? The answer to that is based on your personal experience and budget.

Many experienced reefers will agree that in terms of properly lighting a reef tank, if it is not T5 reef lighting, it should behave like T5s.

What exactly does it mean to act like a T5? You can answer this question with 5 major attributes that will really make it clear why T5 lighting is still quite popular.

BRS Anemone Tank

Produces Results

Above all, T5 lighting is plug and play and will produce results without any tuning. Choose a T5 fluorescent fixture and bulb combo, plug it into a timer and you can be certain that lighting will never be the reason you are not successful.

The facts are, for the most part, LED’s do not produce plug and play results. LED’s have the ability to produce the same or even better results compared to the T5's but it requires effort, experience, intuition, often a bit of luck and expensive PAR meters are required for precise tuning.

Example of par results of T5 vs LED

Even coverage without hot spots

T5 bulbs and reflectors provide highly diffused lighting that coats the tank with a an even blanket of light. This results in minimal shadowing and hot spots.

The small form factor that most LEDs come in these days inherently means the light will be brightest directly under the diode and fall off to the sides creating what we call a hot spot. More or less a wide angle spot light rather than an even blanket of light.

Radion LED over reef tank

The wide angle lenses do a good job of visually making the tank look evenly illuminated but the nature of that light makes it easy to create shadows in the tank. This is particularly true as the tank ages. As corals get larger they shadow not just their neighbors but also themselves. This effect is not so drastic in soft coral or LPS tanks but can be quite severe in SPS dominant tanks.

LED/t5 Hybrid Light Fixture

Many hobbyists will supplement LED lighting with T5 tubes to combat this effect. LED/T5 hybrid fixtures are a great way to take advantage of this.

Orphek LED Light Fixture

There are also some LED fixtures that are designed in such a way to produce a more even spread of light with multiple diodes spread amongst a large layout like the Orphek LEDs but can be significantly more expensive.

Measuring light with PAR meter

No PAR meter required

When choosing a T5 fixture it is just a question of 4, 6 or 8 bulb fixture depending on your light needs and intensity will never be your issue.

With LED lights, there are the intensity sliders, variable mounting heights for different tank shapes and dozens of different brands which all behave differently.

In an attempt to help demystify that we have published in-depth PAR testing results over a variety of tank shapes and light configurations with the most popular LED lights. We also started renting out PAR meters which makes it much more affordable for you to do at home.

ATI Bulb Colors

Well blended color spectrum

T5 bulbs emit a broad and very even color spectrum. Even when using a mix of different bulbs, they all blend together very evenly.

With most reef aquarium LED lights, they are closely bunching individual diodes with single color spectrum peaks and letting them overlap to create a visually blended spectrum. That kind of works, but you can often see the individual spectrums shooting around the tank with the naked eye. It becomes even more obvious when measured because you can see the spectrum bounce around as the light reflects off the water’s surface.

Kessil vs Radion LED layout

LED manufactures have addressed this in a variety of ways. Kessil uses what they call a Dense Matrix in which the diodes are all arranged under a single lens. EcoTech Marine offers an optional diffuser pane to attach to the bottom of their Radion LEDs.

You can improve this color blending of any brand LED by raising it higher. In fact, we observe some of the best performance from an LED when it is mounted 18” from the water’s surface.

ATI Fixture over reef tank

Easy mounting height

It is easy to gauge T5 mounting height because light distribution, coverage and spectrum blending are just not a big concern. Our general advice is simply raise the fixture until you get unnecessary light spill into the room. This is often much closer than what is ideal when using an LED light making them easy to mount.

Radions over the BRS/WWV hybrid tank

Many LED manufacturers suggest mounting 8 - 10 inches from the surface but the fact is many elements of the overall performance get dramatically better the higher you raise them. Avoiding hot spots and achieving full coverage by raising the light until you see it spill over the edge often results in something much higher than the recommended 8-10 inches which we then recommend double checking using a PAR meter.

Understanding how T5 bulbs perform makes it easier to understand why T5 lighting is still a popular choice among advanced reefers.

Id say 90% of reefers are selecting LED’s because of the shimmer, small form factor, adjustability, lack of replaceable bulbs and simple cool factor. It is becoming very common for LED users to add T5 HO bulbs to their existing LED spread with one of the various retrofit kits to gain the benefits of T5.

Check out the in depth BRStv Investigates about the Aquatic Life T5/LED Hybrid Retrofit Kit that shares the data and demonstrates all the benefits of this approach or browse through our entire library of videos all about lighting.

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