Growing SPS corals is certainly an exciting challenge within the reef aquarium hobby. Anyone who has kept SPS knows just how important lighting is when it comes to the world of small polyp stony corals. We are going to break down the lighting mistakes to avoid when keeping an SPS-dominant reef aquarium.

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1. Not Considering Lighting For A Frag vs A Colony

The lighting requirements for an SPS frag are very different from the demands of a full colony. With frags, you will not have to deal with it shading part of its own structure and it should be quite easy to blanket with light compared to a large colony. This doesn’t mean that your lighting won’t be able to grow with you as you progress through the hobby.

2. Not Understanding Shadowing Neighbors Matters

Shifting to small form factor LED’s works great for when your system is filled with small SPS frags, but once they start to grow into colonies, shadowing is an issue that needs to be addressed.

3. Missing The Shadowing Of The Coral Itself

When a frag grows into a colony, it is very possible that certain parts of the colony will shade out other parts and create dead spots. If you can solve shadowing by using a different fixture or a hybrid fixture, it will make your system much more successful in the long run.

4. Thinking A Single Point Of Light Is Enough

To get the intersecting cones of light needed to keep SPS fully lit, you will most likely need multiples points of light. Spacing LED fixtures every 12-18 inches will be the best way to get those intersecting light cones.

5. Light Blanket Option 1: Light Source As Big As Aquascape

To fully illuminate a coral in a blanket of light, the light source must be larger than the coral. Therefore, having a large light source that covers your entire aquascape will allow you to fully cover all of the corals within the display.

6. Light Blanket Options 2: Using Multiple Smaller Lights

To get full coverage using individual fixtures, you will want light fixtures with wide lenses that will send intersecting light cones across the display to make sure your corals are fully illuminated. Creating a grid of AI Prime 16 HD’s is a good way to achieve this method without spending a large amount of money.

7. Light Blanket Option 3: Using Fill Light With A Wide Angle

Using hybrid lighting is a great way to combine unique lighting varieties to get the benefits of each of them without the drawbacks. This actually occurs on Earth on a much larger scale with the sun being the main lighting source and the atmosphere’s reflection of the sun that illuminates the sky as a secondary source. T5/LED as well as T5/Metal Halide hybrid fixtures are an incredible way to illuminate your corals from all angles.

8. Not Considering T5 Lights

Oftentimes, we can be blinded by the allure of the hottest new LED fixture on the market, but there is a reason why many successful SPS reefers still stick with T5 fixtures. Simply put, they just work. T5’s will allow you to plug them in and focus on the other important aspects of keeping SPS. By using T5, you will not need to fiddle around with light settings such as color, brightness, and intensity.

9. Not Considering LEDs As T5 Replacements

Using a collection of LED strips from Orphek or ReefBrite can put out as much if not more light distribution than a T5 fixture. LEDs have come a very long way and now, most fixtures create a properly blended spectrum to promote coral growth. Therefore, you can oftentimes replace T5 bulbs with LED strip lights.

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10. Not Considering That Lighting Just Matters More

There are so many aspects of lighting that are crucial in order to achieve an SPS dominant system. While you can get away with a variety of simple lighting techniques for most basic reef aquariums. These same solutions are not gonna cut it for an SPS-centric reef.

11. Not Understanding That Spectrum Matters

Having a spectrum that caters to SPS specifically will do wonders when it comes to their health and growth. Light manufacturers have done a better and better job of ensuring evenly mixed spectrums with great diffusion. SPS, in particular, prefers a blue heavy spectrum.

12. Not Understanding Proper Blending Is Crucial

Using an LED fixture that does a very good job of blending the light or purchasing a diffuser that will do this for you is a great way to ensure an even spectrum across your aquascape.

13. Not Understanding Stability Matters More

While it may be tempting to constantly adjust your light settings, this is a very destructive process as your corals take time to adjust to your lights. Constantly changing your settings will have them trying to acclimate to your system rather than grow. Setting your lights and forgetting about their controllability is crucial.

14. Spending More Than You Need To

T5 fixtures are quite affordable and as we’ve already discussed, very effective. Additionally, purchasing a few small LEDs can help you save money as opposed to splurging on a bunch of large fixtures. The Aquatic Life Hybrid fixture is a great way to create an inexpensive hybrid unit that is capable of keeping an SPS dominant system on a variety of tank sizes.

15. Not Using A PAR Meter

A PAR meter is the best way to get an idea of the settings on your lighting fixtures that allow you to find the sweet spots in your display for SPS corals. You will want to find a PAR range between 200 and 350 for SPS. Nowadays, the LED fixtures on offer can significantly exceed those numbers and this could potentially damage or kill your corals.

16. Not Understanding What PAR To Shoot For

Between 200-350 PAR is the range that we are shooting for when setting up our light fixtures. Your tank will have parts of it where those numbers are exceeded and parts where they are far below 200. Shooting for the middle of that number at 275 is usually a great place to be.

17. More Isn’t Better

Creating more PAR from your fixtures isn’t something you want to chase. Some corals will do much better in lower PAR areas and in general, having less PAR is much less likely to shock and kill your corals. If you are going to experiment with your corals in different areas of your tank, make sure to do it slowly and for long periods of time.

18. Understanding Higher PAR May Be Better For Color

You will see more color pigment and fluorescence with higher PAR because the coral will create those pigments as sunscreen to protect themselves from UV light. These pigments will reflect some of the light away to make its PAR intake more manageable.

19. Understanding Lower PAR May Be Better For Growth

At a lower PAR value, many SPS corals are actually able to absorb more of the light and use it to grow significantly faster. As long as the coral looks healthy visually and it is growing, you are providing it with enough PAR.

20. Not Realizing That Higher Par Requires Higher Flow

The more energy being put into the coral and the more it has to protect itself, the more those bi-products created by the corals need to be flushed away. These oxidants are actually toxic and if they are not able to shed them, they will release their zooxanthellae and will most likely die. It is important to find the slow flow spots in your system and solve those areas to improve your results.