A Comprehensive Guide To High Light Corals

Keeping high light corals can transform an aquarium into a stunning underwater oasis, but they require some special care. If you’re short on time, here’s a quick answer to your question: high light corals need strong lighting, excellent water quality, proper flow and stable water parameters to thrive in a reef tank.

In this comprehensive guide, we’ll cover everything you need to know about successfully keeping high light corals. We’ll discuss proper aquarium setup, lighting requirements, water parameters, flow needs, feeding, pests to watch for, and our top high light coral recommendations.

What Are High Light Corals?

High light corals are a group of corals that require intense lighting to thrive. They include many popular aquarium corals like small polyp stony (SPS) corals and large polyp stony (LPS) corals. With proper lighting conditions, high light corals can grow quickly and produce vibrant colors in reef aquariums.

Photosynthetic Corals

One of the defining features of high light corals is that most of them contain symbiotic algae called zooxanthellae. The corals provide the algae with shelter and nutrients, while the algae produce energy through photosynthesis. This energy fuels the coral’s rapid growth and bright colors.

More light equals more photosynthesis and faster coral expansion.

Fast Growth in Proper Conditions

Given strong lighting, high light corals can grow at incredible rates. SPS corals like acropora and montipora can expand over an inch per month with optimal conditions. This makes them popular for aquarists wanting to quickly fill out a reef tank. However, fast growth requires stability.

Changes in lighting, nutrients, or water chemistry can cause high light corals to decline rapidly as well.

Include SPS and LPS Corals

The most common high light corals kept in reef aquariums include:

• Small polyp stony (SPS) corals – Acropora, pocillopora, montipora, and stylophora species are popular options. They have small, colorful polyps.
• Large polyp stony (LPS) corals – Euphyllia, scolymia, cynarina, and blastomussa species. They have larger fleshy polyps.
• “Tree corals” like capnella and pocillopora, which grow in vertical branches.
• “Candy cane” and “trumpet” corals in the caulastrea family, known for fluorescent colors.

Providing these corals with strong lighting allows aquarists to replicate stunning coral reef ecosystems at home. However, high light also comes with challenges like potential algae growth and the need for stable water quality.

High Light Coral Aquarium Setup

Large Tank Volume

When keeping high light corals that have fast growth rates and higher demands, it is recommended to have a larger tank volume (e.g. 90+ gallons). The greater water volume helps dilute waste products and maintain stable water parameters. Large tanks also tend to be more forgiving of errors.

High Output Lighting

Proper aquarium lighting is crucial for photosynthetic corals. High output metal halide or LED systems that provide intense light at levels of 300-500+ PAR at the substrate are ideal. This allows sufficient light for fast growing SPS corals and coral colors to pop.

LEDs run cooler and more energy efficient than metal halides.

Protein Skimmer

Having an efficient protein skimmer rated for at least twice the water volume helps remove organic waste from the water column before it breaks down into nitrate. This is vital for maintaining low nutrients to prevent algae growth in high light tanks.

Refugium

A refugium is essentially a separate sump section that can grow macroalgae. Refugiums are great natural nutrient export systems as the macroalgae uptake excess nutrients like nitrate and phosphate. Chaetomorpha is a common choice. This further helps control nutrients and enhance water quality.

Providing Proper Lighting

PAR Levels for High Light Corals

Proper lighting is crucial for keeping high light corals healthy and vibrant. The key metric for lighting is PAR, which stands for Photosynthetically Active Radiation. High light corals typically need PAR levels between 200-400 micromoles per square meter per second (μmol/m2/s).

This intense lighting allows corals to photosynthesize, produce vibrant colors, and grow quickly. Selecting metal halide or LED lighting that provides adequate PAR levels in the proper spectrum range is essential.

Metal Halide or LED Lights

The two most common lighting options for high light reef tanks are metal halide and LED lights. Metal halide lights put out intense light in the blue spectrum that corals need. However, they run hot, use lots of electricity, and need to be replaced yearly.

LED lights are much more energy efficient, run cooler, and last longer. Quality LEDs designed for coral growth put out a strong blend of blue and white light. Either metal halide or LED can work well as long as they provide high PAR at the right color spectrum.

Light Duration and Intensity

In addition to using the right type of light, the photoperiod (duration lights are on) and intensity must be properly balanced. High light corals often thrive with 10-12 hours of intense light per day. However, start with 8-10 hours and gradually increase to prevent shock.

It’s also wise to ramp up intensity over the photoperiod, with peak intensity in the middle of the day. This mimics the natural increase and decrease of sunlight throughout the day. Providing too much light for too long can bleach and eventually kill corals.

Supplemental Lighting

For tanks deeper than 18-24 inches, the primary lighting may not provide enough PAR at the substrate level. Supplementing with additional LED spotlights on select corals can help ramp up the intensity.

This focused lighting ensures all corals get the light they need, even when shaded by rockwork or positioned lower in the tank. Just be sure not to create hotspots that burn corals. Proper lighting is all about balance – too much or too little can cause issues.

Maintaining Stable Water Parameters

Keeping consistent and stable water parameters is crucial for the health and growth of high light corals. Even slight fluctuations outside the optimal ranges can cause corals to become stressed, lose their coloration, stop growing, and even die if extremes persist for too long.

By regularly monitoring and maintaining levels of temperature, pH, alkalinity, calcium and other important elements, aquarists can help ensure their corals continue to thrive in aquarium conditions.

Temperature

Water temperature has a major influence on coral health. Each species has an ideal temperature range it is adapted to in the wild. In general, most high light corals prefer a range around 78-80°F. Temperatures lower than 75°F or higher than 82°F for extended periods can start to impair coral growth and cause bleaching.

Use reliable aquarium heaters and chillers to keep temperatures stable near the 78-80°degree;F optimal zone. Avoid fluctuations of more than 2°F up or down over a 24 hour period. Carefully monitor temperatures daily to catch any equipment issues before extremes occur.

Consider using a failsafe controller to shut off equipment if unexpected temperature spikes happen.

pH

The pH indicates water acidity and alkalinity. Corals need stable, mildly alkaline pH levels between 8.1-8.4 to properly grow and calcify their skeletons. At lower pH, their skeletal structure becomes weakened. Rapid pH drops below 8.0 can even kill corals quickly during acute acidification events.

Test pH often, at least twice per week. Use buffers, calcium reactors or dosing pumps to maintain pH in the 8.1-8.4 range. Having adequate alkalinity and calcium levels also helps buffer against pH crashes.

If the pH starts dropping rapidly, act quick to investigate and correct the cause – whether equipment failure, CO2 buildup or other issues.

Alkalinity

Alkalinity represents carbonate hardness and buffering capacity. Maintaining proper alkalinity is crucial for keeping pH stable in the 8.1-8.4 zone. It also provides essential carbonate ions needed for corals to build their skeletal structures. Target levels are usually 8-12 dKH for mixed reef tanks.

Use alkaline buffers or calcium reactors to restore levels if they start dropping more than 1 dKH in a short period. Test alkalinity weekly or more to ensure it remains in the ideal 8-12 dKH zone. Having both adequate alkalinity and calcium makes it easier for corals to grow quickly under high light.

Calcium and Other Elements

Calcium is the most important mineral for coral growth. High light corals need elevated calcium levels around 450-500 ppm to accommodate their rapid calcification rates. Magnesium, strontium and other trace elements are also essential for proper skeletal development.

Monitor calcium and magnesium levels weekly to monthly based on coral growth rates. Use two-part solutions, calcium reactors or other methods to maintain calcium around 450-500 ppm and magnesium around 1350-1500 ppm. Also dose essential minor and trace elements according to tank needs.

Having the right balance of minerals allows coral growth and coloration to thrive under high lighting.

By vigilant monitoring and correction of any water parameter issues, aquarists can help ensure their high light corals continue growing rapidly and showing beautiful coloration for years to come. Advanced controllers and dosing systems also make maintaining optimal and stable conditions much easier for the reefkeeper.

Ensuring Adequate Water Flow

Proper water flow is crucial for the health of high light corals. The movement of water brings fresh oxygen and nutrients while removing waste. High light corals have high rates of photosynthesis and respiration, meaning they need consistently high flow.

Here’s what you need to know about providing adequate current in your reef tank.

Minimum Flow Rates

As a general rule, high light corals need a minimum of 10-20 times the tank’s volume per hour. For example, in a 50 gallon tank you’d need around 500-1000 gallons per hour (gph) of flow. More is often better when it comes to current – some aquarists use up to 40x turnover rates in high light reefs!

Powerheads and Wavemakers

The easiest way to generate increased flow is by adding powerheads and wavemakers. These standalone water pumps allow you to precisely control flow rate and direction. Strategically aim pumps to create a randomized wave pattern that reaches all areas of the tank.

When using multiple powerheads, make sure they pulse on separate timers to prevent excessive pulses.

Arranging Rockscape for Flow

The rockwork and reefscape also plays a key role in flow dynamics. Arrange boulders and structures to promote multiple flow paths without excessive turbulence. Generally, porous structures divert and slow down current, while solid walls and overhangs create faster rushing flow.

Using a mix of both porous and solid structures allows you to create flow variability.

Testing flow rates with a velocimeter is the best way to fine-tune the reefscape and equipment. Shoot for 5-10x turnover in most areas, with 15-25x in high flow zones. This creates the randomized, dynamic flow that corals thrive in! For more on reef tank flow, see this detailed guide.

Feeding High Light Corals

Photosynthetic Corals Still Need Some Food

Even though high light corals get most of their nutrients from photosynthesis, they still need some external food sources to thrive. The zooplankton they catch simply isn’t enough in captivity. Supplementing their diet helps them grow faster and become more vibrant.

Target Feeding

The best practice is to target feed your corals by using a pipette or turkey baster. This ensures the food gets directly to the corals rather than being filtered out or eaten by fish first. Target feeding allows you to observe each coral’s feeding response too.

Liquid Coral Foods

Liquid coral foods are easily absorbed and contain amino acids, plankton, vitamins and fatty acids. Great options are Reef Roids, LRS Food for Corals, Coral Frenzy, Cyclop-Eeze and Coral Snow.

Feed at Night

Corals have tentacles they extend at night to capture food. Feeding them when they are open and eager to eat allows your corals to get maximum nutrition. Turn off pumps and powerheads and use red LED lighting at night to watch their fascinating feeding process!

Pests and Problems to Watch For

Algae

Unwanted algae growth is one of the most common issues in coral aquariums. Filamentous algae can quickly overrun your tank and smother your corals if nutrients and lighting conditions allow it to thrive.

The best defenses are stable water parameters, proper husbandry, avoiding overfeeding, and keeping nutrient export high through protein skimming, water changes, and algae eating clean up crews like snails and hermit crabs.

Aiptasia Anemones

The scourge of coral aquarists, Aiptasia anemones can reproduce rapidly and sting neighboring corals. Manual removal works for isolated occurrences, but most aquarists turn to commercial pest control products when aiptasia become more widespread.

Products containing Aiptasia-X or berghia nudibranchs offer fairly effective biological control if applied properly.

Coralline Algae Loss

That beautiful pink coralline algae coating your live rock is sensitive to changes in alkalinity, pH, lighting, and water flow. Losses typically indicate an underlying husbandry issue. Test and restore proper alkalinity levels. Improve flow and diffusion in dead spots with powerheads.

Adjust lighting duration and spectrum if coral health declines. Slow coralline growth hints at suboptimal reef health – fixing it should be a priority.

Bleaching

Coral bleaching is a stress response where the coral expels its symbiotic zooxanthellae algae, causing a stark white appearance. If the stressor persists too long, the coral will die. Common bleaching triggers include high/low temperatures, salinity swings, high lighting, low nutrients, sedimentation, and disease.

Improving husbandry is key, but even then, occasional random bleaching can occur. Have backup frags available for insurance!

Best Beginner High Light Corals

Montipora

Montipora are absolutely stunning beginner corals that come in a variety of different colors and growth forms. They have rapid growth rates and are relatively easy to care for as long as they receive enough light.

Some popular Montipora species for beginners include M. capricornis, M. digitata, and M. confusa. Provide plenty of water flow and watch them grow into eye-catching centerpieces in your tank.

Acropora

The brightly colored branches of Acropora corals make them enticing options for new hobbyists. Acropora millepora, also called “cabbage coral”, is a particularly hardy species that can tolerate a wide range of conditions. Other beginner-friendly Acroporas are A. gemmifera, A. nasuta, and A. valida.

Give them strong lighting and watch them flourish into stunning coral formations. Just be aware they can be prone to rapid tissue necrosis if care parameters fluctuate.

Pocillopora

With their delicate branching structures and vivid hues, Pocillopora are exceptional starter corals. P. damicornis is likely the most popular species, available in an array of color morphs like neon green, pink, and purple.

These corals are fast growing, hardy, and relatively forgiving of minor husbandry mistakes. Other great beginner Pocilloporas include P. meandrina, P. verrucosa, and P. eydouxi. With proper light and flow, they will thrive and add lovely color to any reef tank.

Stylophora

If you want coral with serious wow-factor, Stylophora is sure to impress. These corals have chunky, digitate plates in stunning hues like metallic greens, blues, and pinks. Popular starter species include S. pistillata and S. subseriata.

With adequate lighting, water movement, and stable water quality, Stylophora makes an excellent choice for beginners. Growth rates are moderate to fast depending on conditions. In good health, they will become stunning showpieces on the rocks.

Conclusion

With the proper setup and care, high light corals can make an incredible addition to any reef tank. Focus on providing strong light, stable water quality, adequate flow, and occasional target feeding. Monitor corals closely and address any pest or problems right away.

For beginners, montipora, acropora, pocillopora and stylophora are great first corals to start out with. Follow this guide and you’ll be on your way to keeping spectacular high light corals!