Reef aquarium lighting is one of the most important pieces of equipment on your tank and plays a critical role in maintaining and growing healthy corals. Through this episode you will learn how to choose your light, how to set it up and gather a few valuable tips to avoid the common mistakes.


T5 Fluorescent Lighting


There are four things you need to consider and understand when choosing and setting up your reef aquarium lighting system.


1. Coral Health - Every discussion about reef lighting should start with optimal coral health because corals rely on light and photosynthesis for a majority of their energy.
2. Coloration - We keep reef tanks because we think they look cool. In order to achieve that living piece of artwork you imagine, proper lighting is mandatory and plays a huge role in a corals coloration and appearance.
3. Aesthetics - In the same way we want the tank display itself to be impressive, the overall appearance of the entire system is important. The light fixture is part of that overall aesthetic.
4. Price -We all want to find lighting solutions at a reasonable price. Solid , reliable lighting options which meet these goals won’t be the cheapest thing you get for your tank but you shouldn't have to get a second mortgage either.

Aqua Illumination Prime 16 HD LED Light


In addition to these generally universal requirements, you need to consider your own wants and desires which very well may change from reefer to reefer or tank to tank. So just like what we established above, write a list of your goals and manage your tank and lighting solution to help you achieve them.


Aqua Illumination Prime LED Lights over 40 breeder


Aqua Illumination Prime 16HD LED Light

For our 40 gallon breeder, we picked out two of the Aqua Illumination (AI) Prime 16HD LED lights which are, honestly, one of the best choices out there. Especially when we consider our goals previously discussed and our desires for coral in this tank build.


Aqua Illumination is one of the most established reef aquarium lighting companies. The fixture has all of the important spectrums for coral growth and is perfectly balanced for this tank size in terms of output or power.


AI Prime Led lights over 40 breeder, side view


You will need two Prime LEDs to create a wide enough spread of light over the 36” long tank. The output is sufficient for the type of corals we plan to keep and if you ever decide you need more light, simply add another fixture and space them closer together. The spectrum the AI prime puts out also highlights the corals natural fluorescence really well and produces a high contrast, visually interesting tank.


Aqua Illumination Prime mounting arms


There are two mounting options, the flex arm and the fixed mount. We ended up going with the fixed mount here because it looks sharp and the low profile of the fixtures just looks sharp on this tank. No bulky wires, no hanging cables or chains, no bulky light racks and still plenty of room to access the top of the tank.


Red Sea ReefLED Light


Red Sea E170 ReefLED

The Red Sea E170 comes with a light so you don’t have to think about it. This tank is closer to a square shape so you can light it efficiently with a single, higher powered light source like the included Red Sea ReefLED.


We mentioned this earlier in the series but the included gear like this ReefLED are part of the reason these AIO tanks really end up being not all that much more expensive compared to their standard counterparts.


Red Sea ReefLED Light


A mounting arm is included and simply follow the instructions included with the tank. Assembly is minimal in this case and after getting it mounted, your next step is setting the color, intensity and time schedule.


How to Program Your Aquarium LED Lights

The easiest way to set up a programmable LED light such as the AI Prime HD or Red Sea ReefLED is to listen to those who came before you and learned the hard way.


LED lighting has some major benefits over fluorescent or metal halide lighting options of days past but you can easily do the wrong thing if you start to ignorantly tweek the output and spectrum.


LED Light Programs for Red Sea ReefLED and Aqua Illumination Prime


To make it easy, simply follow the guidelines pictured here which have been proven optimal for the types of corals we plan to keep. If you tune the lights using these settings with somewhere close to a 10 hour light cycle, lighting will not be a challenge on either of these tanks.


Blues are often the most predominant because that is the spectrum peak (color) that matters most to the corals. Add white colored light until you like the way it looks. Be very careful with the red and greens, anything more than 20% is unnaturally high in most cases but it does depend on the exact light fixture.


Notice the ramp up and ramp down cycle at the end of the photoperiod (timed light cycle). This is not because the corals require that gradual change but it does allow you to view the tank longer at lower intensities.


PAR Meter


If you are building a different tank or using different lights than what we have here our best advice is to rent a par meter which measures the strength of light. Rental cost is only $50 and allows you to intelligently tune your output rather than guess. While this is definitely an extra step and extra expense, you will drastically increase your chances of success.


  • Soft Corals and LPS: 75 - 150 PAR
  • SPS Corals: 250 - 350 PAR

Using the guidelines above, measure lighting throughout your tank and adjust the output accordingly to achieve the desired PAR throughout as much of the tank as possible


Zoanthid colony


Here comes those golden nuggets of advice that we promised would help you succeed. First, PAR is not horsepower! What this means is more light is not better. In fact, you are far more likely to kill corals with too much light than you are not enough. Resist the temptation to ride that edge and be conservative with your lighting customization and changes.


Also, don’t go thinking you can gauge the PAR with your eyes. The usable light for corals (PAR) and the spectrum our eyes perceive as brightness are totally different. Our eyes naturally auto iris based on brightness as well so you can never really be an accurate judge. Some reefers may get close by luck, intuition or solid advice but it is far from easy for any reefer to estimate PAR.


Duncan Corals irritated and retracted


That said, you can guess and watch how the corals tolerate it. Start low and work your way up in terms of intensity. Even though this is a lower percentage path, it is by far the most common.


If the light is too bright or PAR is too strong, the corals will shrink up and retract tissue to protect themselves from the intense light. If your light output is insufficient, they will get puffy, stretch out, reach or expand themselves to try and create more surface area to capture more light.


Duncan coral polyp


“Corals are amazingly adaptive creatures and will adapt to almost any of our mistakes if you just let them be.” Victor from worldwidecorals.com.


What this means is you don’t have to get it perfect to be successful but you DO need to resist the temptation of touching the color sliders frequently or constantly changing the photoperiod. You really want to set it and forget it.


What’s Next?

Now that our tanks have light, the next step is tackling one of the biggest components of your life support system, your protein skimmer.


5 Minute Saltwater Aquarium Guide Episode #14


Looking for a different topic or have questions? You can binge the entire 5 Minute Saltwater Aquarium Guide playlist right here on our website. We also invite you to join the #askBRStv Facebook Group which is a free resource for you to ask questions, get advice, interact with other hobbyists and get your daily reef aquarium fix.