DETAILED GUIDE TO REEF TANK LIGHTING
It's no secret that the right lighting can change the dynamics of your reef tank. While it is common in North America to run the systems more towards the blue spectrum, many of our friends in Europe enjoy reef tanks lit with a whiter spectrum. The great news is that with the advent of modern LED reef lights, many can achieve the perfect balance of both. Many modern LED Lights are capable of programming their spectrum, including ramp up and ramp down, channel strength, and minute by minute configurability. We highly recommend hobbyists invest in a good lighting rig for their system if maintaining healthy stony corals is the goal.
At Reef Chasers we implement different lighting fixtures on different systems that range from Kessil AP9X, Radion G5, T5, Photon's, Reef Brites, AI Prime, Neptune Sky's and at times these fixtures are mixed together. Mostly this is the hobbyist in us, wanting to try out all the different tech and implement it to its fullest. About the only thing we don't use at Reef Chasers is Metal Halides, but below we will discuss how we mimic them in our schedules.
Some of the most popular LED lights for hobbyists include: Kessil, Radion, Neptune, Reef Brite, Photon, AI, Orphek and others. In our experience, all of these lights are capable of delivering excellent performance when needs are understood and implementation is correct. When choosing the right lights for your reef tank you should first define your needs.
How much power do I need? How big and deep is the tank?
Modern reef LED lights are going to have an easily researchable wattage rating and this can clue you in as to the power the light is capable of producing.
- 1-10 gal: 10-30 watts
- 10-20 gal: 30-60 watts
- 30-40 gal: 40-80 watts
- 50-60 gal: 80-100 watts
- 60-80 gal: 100-130 watts (consider multiple fixtures)
- 100-120 gal: 130-180 watts (consider multiple fixtures)
- 150+ gal: 200-400+ watts (consider multiple fixtures)
How evenly would I like the display lit?
- With many modern LEDs you will find that a single fixture will be 'hot' right underneath the bulbs but will wane as the light waves spread outward. This means that you are unlikely to want to run a single fixture at 100% to light a large display tank. Rather you are more likely to run two or more fixtures at 30-60% depending on your corals needs, water clarity, and tank depth.
- In some cases 'hot' may be desirable, such as in a mixed reef. You may want to juice up the center with high par (300-400+) while getting dark towards the edges to support low light corals on the outskirts. It's important to remember you can do mixed reef with multiple fixtures as well and let the elevation control your placement (low light corals go to the bottom, and high light ones to the top.)
- At Reef Chasers we like even par distribution so that we can split up our tanks by species and not have to do a whole lot of thinking about individual coral placement. For example we may want the entire 8ft x 4ft farm tank to be an even 350 par. To achieve this we use more LED fixtures, run at lower overall percentages and supplement them additional with T5 florescent bulbs which are known for their lack of shadows and even light diffusion. T5's use much more energy then LED lights, produce more heat, and are less aesthetically pleasing. For these reasons, many hobbyists achieve great success with 100% LED Lighting and skip the T5 supplementation entirely.
WHAT SPECTRUM DO I WANT?
- Many modern LED's can achieve excellent results and allow the user full configuration over ramping, scheduling, and spectrum, this can allow the hobbyist to dial in there exact look and other requirements and to fine tune them precisely. Many modern LED's have strong UV Channels which are important to corals. At Reef Chasers we use a lot of Kessil AP9X fixtures but also have systems running on Neptune Skys, Orpheks, Photons, Reef Brites and Radion G5s. In our Experience all of these brands offer great results depending on implementation.
- T5's tend to produce whiter spectrums although there are popular blue bulbs that make this a cooler white. Most people who use T5s run a lot of Actinic bulbs as T5 actinic's provide great growing spectrum for corals in the 390-410nm range. T5s are not energy efficient. At Reef Chasers we run a mix of 6 actinic bulbs and 2 blue bulbs. We get the majority of our blue from our LED fixture and rely on the supplemental T5 fixture for actinic 390-410nm primarily.
- Metal Halides produce whiter, warmer light and are high powered and deep penetrating. They use a lot of power, produce a lot of heat but are known to be the strongest grow lights on the market. Many hardcore SPS Collectors may opt to experiment with these types of lights although it's important to note many hobbyists have achieved great success with 100% LED fixtures. Metal Halides are not energy efficient. At Reef Chasers we do not use Metal Halides although we simulate their use in our LED schedule (discussed below).
LIGHT SCHEDULE & SPECTRUM
The lighting schedule has an important role in the dynamics of your reef system. At Reef Chasers we implement a twelve hour light schedule on all of our systems. This schedule includes a two hour ramp up and ramp down on each end, with an eight hour main photo period between. Our twelve hour schedule serves two purposes: First it closely mimics nature, which is what we strive to do as often as possible. Secondly, the twelve hour schedule leads to higher, more stabilized pH over time which we will discuss further below.
At Reef Chasers we tend to keep our Violet/UV channels at 100% for most of the duration of the schedule. We feel that 390-410nm is one of the most important wave lengths for coral growth and so UV/Violet channels are the most important to us. We tend to run around 10-12k for the main 8 hour photo period which is a cool white/blue "full spectrum" like one might find on Radion's AB+ or Kessil Tuna Blue. One trick we have implemented on some of our systems is to do a high noon "bump" to simulate the effect of metal halides for three hours in the middle of the twelve hour schedule. During these three hours we increase the LED's intensity by 10-20% and shift the lighting more towards the warmer white 7k spectrum.
When we mention light channel intensity below, we are not referring to the overall light intensity of the led fixture. You may have your UV and Heavy blues at 100%, but the overall intensity set to only 30%. Overall intensity depends on the requirements of the corals you keep and there for we cannot give a blanket statement. With high powered modern LED's like Neptune, AP9X, AI Prime or Radion 4g/5g 30-40% is good for most LPS corals, but some might like as low as 10-20% depending and up to 60-70% for Acropora. These percentage intensity recommendations may change if you have a large system with only a single fixture, or a multiple fixture configuration such as 3 fixtures side by side that will run at lower percentages and produce more intensity then a single at a higher percentages.
REEF CHASERS LIGHTING SCHEDULE (with high noon metal halide simulation)
- 6AM: LED's turn on at 0% on all channels, 0% intensity. UV and Heavy Blue channels ramp up to 100% over first hour. Intensity ramps up to our systems desired intensity (see above)
- 7AM: Other channels start to ramp up.
- 8AM: Main photoperiod begins. All channels and intensity are at their desired settings. Our supplemental T5s turn on.
- 10:30AM: Our LED Halide Simulation Ramp starts
- 11:00AM: Our LED Halide Simulation in full effect. Spectrum shifted whiter/warmer and more intense +10/20%
- 1:00PM: Our LED Halide Simulation ends
- 1:30PM: Ramped back to main photoperiod spectrum/intensity.
- 4:00PM: Main photoperiod ends. Our supplemental T5s turn off. Heavy blues and violets remain at 100%
- 5:00PM: All other channels ramped down, heavy blues and violets remain at 100% but will ramp down over final hour.
- 6:00PM: All light channels have ramped down to 0% and moon lighting begins.
Each reef tank has different dynamics and the needs of the hobbyist's unique system will ultimately dictate the lighting schedule and spectrum choices. We recommend twelve hours total length regardless, but you could have success with ten, eight, or even as low as six hours if done correctly (higher intensity offered for shorter period, etc). An advanced reefer can and will fine tune their lighting system and schedule as their system advances.
Please note hobbyists DO NOT NEED T5 Fixtures. Modern LED lights have made the benefits almost completely obsolete. We only use them at reef chasers to eliminate shadows and get perfectly even par distribution across large tanks. Most hobbyists DO NOT have this requirement "perfectly even par distribution" As they are housing many types of corals within same tank and prefer to have high and low light zones throughout.
LIGHTING IMPACT ON ALGAE GROWTH
We have never really found our lighting or schedule length or spectrum to impact algae growth. If anything, restricting/restraining your light hurts your systems pH and there is some science to suggest lower pH environments are more advantageous for various turf algaes. In nature, as pH in the water rises the likelyhood of encountering turf algae decreases where as zones that are overrun with turf algae have chronic low pH. It is theorized Turf Algae creates a self-enforcing feedback loop that helps drive and stabilize LOW pH. Bottom line: Algae will grow just fine under blue lights and keeping your schedule short or blue will not prevent algae infestations. Although there may be other reasons to favor blue lighting spectrums, fighting algae is not one of them. You cannot starve algae to win a battle against it, whether that is with nutrients or light. If you attempt a starvation strategy the outcome is grim for your corals.
LIGHTING IMPACT ON PH
Do to the diurnal nature of photosynthesis in our reef tanks, lighting can have a great impact on pH. During photosynthesis CO2 is removed from the water column and replaced naturally with Oxygen. It is one of the main reasons we recommend a natural twelve hour schedule at Reef Chasers. By having a twelve hour lighting schedule you are increasing your average pH as well as stabilizing the day-time night-time swings to be as small as possible. Your reef tank is going to like that a lot! Many hobbyists sleep on this feature of the lighting schedule, but since you're reading/following Reef Chasers, you won't have to worry about missing out on cool ideas like this one!
We also recommend heavy lighting white/warm/red lighting in either an over-sized Algae scrubber or a refugium in your sump at night. Red light may lead to slightly 'faster' growth rates in algae, but any light will do. This extra photosynthetic boost on a "Reverse schedule" from your main lighting period can help to further increase and stabilize your pH. It is often not adequate to fully reverse the effects of night on your tanks pH but every little bit helps!
WATER CLARITY IMPACTS LIGHTING
That's right, some people don't realize that the actual clarity of their water is affecting their lights ability to penetrate as deep and powerful as it may have used to. Cleaning the water column of debris such as using filter socks or implementing activated carbon either with a reactor or other means can help drastically improve water clarity. Insuring good return flow and proper tank turn over also help keep water clear. As the water column dirties it tends to develop a hazy, yellow tin and this will reduce your lights effective par.
LIGHTING CAN IMPACT CORAL COLORS AND HEALTH
- Coral health can be impacted by too much light, resulting in bleaching/stressed coral. Although this is not the only thing that can effect coral health it is important to start low and find the proper placement for the coral by raising the coral up higher towards the light rather than the other way around. Too much light can bleach and even kill corals quicker than you'd think.
- For almost all corals, coral color and overall health can be improved by finding the most desirable spectrum and intensity for a specific corals needs. For most corals this shift in color ranges from duller or even bleached out to vibrant, deep, florescent coloration. It is rare that a coral is actually able to change its entire color (For example blue to pink), but for a select few such as Acropora it is possible.
- For Acropora spp. entire colors can manifest or disappear depending on the spectrum, intensity and length of the lighting schedule. Many Acropora will become dull or brown during shipment or shortly after receiving and sadly it can take many months for them to color up. Truthfully, that coral may never achieve the same color in your tank unless you are providing what it needs to shine. The effect of lighting intensity and spectrum on Acropora coloration tends to go hand in hand with both Alkalinity and over all nutrition and is a complicated process involving different biological interactions. It is only partially understood by even the most advanced reef keepers. We do not recommend people push the limits with their reef systems but we do want them to know that increasing nutrients and adjusting lighting can have dramatic impacts on exactly what colors are seen from these corals.