SPS & Acropora Coral Care Guide

Acropora are some of the most colorful, fast-growing and structurally interesting corals in the hobby. They are also very good at exposing weak spots in a reef system.

Keeping Acropora successfully is less about finding a secret PAR number or copying somebody else’s dosing schedule. It is about providing strong, variable water movement, appropriate light, available nutrition and remarkably boring water chemistry.

What SPS means—and why Acropora is the baseline

“SPS” means small-polyp stony coral. It is useful aquarium shorthand, not a scientific group or a single care recipe. Acropora, Montipora, Pocillopora, Stylophora, Seriatopora and some Porites are commonly sold as SPS, but their light tolerance, flow preferences, growth forms and sensitivity can differ considerably.

This combined guide uses Acropora as the advanced-care baseline because it is generally the least forgiving of rapid environmental change. Montipora and some Pocilloporids may settle comfortably under somewhat lower light or less intense flow, but they still benefit from the same foundation: measured acclimation, varied circulation, stable alkalinity, available nutrients and careful pest inspection.

• Acropora: Often prefers stronger light and flow after acclimation and reacts quickly to instability.
• Montipora: Frequently more approachable, but vulnerable to alkalinity swings, shading and Montipora-eating nudibranchs.
• Pocillopora and Stylophora: Often hardy once established; dense growth can trap detritus or shade inner branches.
• Seriatopora: Can grow quickly but may respond sharply to chemistry or temperature changes.
• Porites: Often durable after acclimation, though light preference varies by species and growth form.

Use the ranges below as starting context, then adjust for the actual coral and its source system. The animal in front of you outranks the category label.

If your reef is mature, your testing is reliable and you can keep alkalinity, temperature and salinity from wandering around, browse our SPS Acropora collection. If every maintenance day becomes a chemistry rescue mission, stabilize the system first. The coral will still be there when the tank is ready.

Are Acropora difficult to keep?

Acropora are generally considered advanced corals because they react poorly to rapid environmental changes. A frag may tolerate a parameter that is outside somebody else’s preferred range, yet struggle when that same parameter changes sharply.

They are best suited to reef keepers who have:

• A mature, biologically stable aquarium
• Reliable temperature and salinity control
• Consistent alkalinity, calcium and magnesium supplementation
• Adequate lighting with a measured acclimation plan
• Strong, variable flow
• Reliable nitrate and phosphate testing
• A quarantine and pest-inspection process
• Enough patience to change one thing at a time

Tank age alone is not a qualification. A younger system with stable biology, calibrated equipment and an attentive keeper may outperform an older aquarium that swings every weekend.

Acropora should not usually be your first coral. They make more sense once you can identify normal coral behavior, understand your system’s daily consumption and distinguish a real trend from one suspicious test result.

Acropora lighting and gradual acclimation

Most Acropora require moderate-to-high reef lighting, but there is no universal PAR target for the entire genus. Species, growth form, source system, spectrum, photoperiod, nutrient availability and prior acclimation all influence how much light a particular coral can use.

Many captive Acropora are maintained somewhere around 200–450 PAR, while some established colonies are grown above or below that range. Treat that as context, not a prescription.

The safest approach is to:

1. Ask what lighting and approximate PAR the coral previously received.
2. Measure PAR at the proposed placement in your own aquarium.
3. Begin below the intended final intensity.
4. Increase intensity or move the coral upward gradually over several weeks.
5. Watch tissue color, polyp behavior and growth before making another adjustment.

A coral arriving from shipping has already experienced darkness and stress. Putting it directly under your brightest setting adds another abrupt change at exactly the wrong time.

Use your fixture’s acclimation mode when available, reduce intensity temporarily or begin the frag in a lower position with appropriate flow. Avoid changing intensity, spectrum and placement simultaneously unless the coral is in immediate danger.

Paling, loss of fluorescence or retracted polyps after a light increase can indicate that the adjustment was too aggressive. Browning does not automatically mean “more light needed,” and pale tissue does not automatically mean “more nutrients.” Confirm the rest of the system before reaching for the slider.

Strong, random water flow

Acropora generally benefit from strong, turbulent and multidirectional flow. Good flow:

• Improves gas exchange around the coral
• Carries dissolved and particulate nutrition
• Removes mucus and waste
• Prevents detritus from settling between branches
• Supports more even exposure as a colony grows

Pump turnover numbers are a poor substitute for observing the coral. Rockwork, pump placement and colony shape determine what actually reaches the tissue.

Aim for vigorous movement that changes direction and reaches the entire coral. Polyps may move or pulse, but the tissue should not be pinned continuously to one side. A narrow, constant blast can damage tissue even when the rest of the aquarium technically has “high flow.”

Reassess flow as frags become colonies. A pump arrangement that worked for a one-inch frag may leave the interior of a mature colony stagnant.

Stable alkalinity, calcium and magnesium

Acropora build calcium-carbonate skeletons rapidly when conditions support growth. That creates steady demand for alkalinity and calcium, with magnesium helping maintain the surrounding carbonate chemistry.

A common conservative operating area is approximately:

• Alkalinity: 7–9 dKH
• Calcium: 400–450 ppm
• Magnesium: 1,250–1,400 ppm

Successful systems operate outside these bands. The important point is to choose a reasonable level that suits your salt mix, nutrient availability and supplementation method—and then keep it steady.

Do not raise alkalinity simply because faster growth sounds appealing. Higher alkalinity can work, but it also increases consumption and precipitation risk and may leave less room for error. Rapid corrections can be more damaging than the original reading.

Track alkalinity frequently until you understand the aquarium’s daily demand. Recheck any surprising result before making a large correction. Adjust dosing when consumption changes due to new frags, colony growth, equipment maintenance or seasonal pH changes.

Nitrate and phosphate: available, controlled and not blindly zero

Acropora need nutrition. Their symbiotic algae provide photosynthetic energy, while dissolved nutrients, captured food and normal fish feeding contribute nitrogen, phosphorus and other materials needed for tissue maintenance and growth.

Do not treat undetectable nitrate and phosphate as proof of exceptional water quality. A test reading of zero may mean nutrients are being consumed as quickly as they enter the water, that the test cannot resolve the concentration or that the system is genuinely nutrient-limited.

Phosphate starvation—especially when nitrogen remains available—can disrupt the coral-symbiont relationship and increase susceptibility to light and temperature stress. Excessive nutrients can create different problems, including nuisance algae, darker coloration and reduced calcification. The goal is availability without uncontrolled accumulation.

Many successful home SPS systems maintain roughly:

• Nitrate: 2–20 ppm
• Phosphate: 0.03–0.15 ppm

These are practical observation bands, not universal requirements. Tanks can succeed above or below them. Trends, balance and coral response matter more than copying the decimal places from another aquarium.

If nutrients are falling, first review feeding, fish load and export equipment. Adjust skimming, refugium lighting, filtration or feeding gradually. If dosing nitrate or phosphate becomes necessary, use a known aquarium product, measure carefully and change slowly. Do not make simultaneous large changes to nutrient input, lighting and alkalinity.

Temperature and salinity stability

A practical temperature range for many captive Acropora systems is approximately 76–81°F (24.5–27°C). The best setpoint is one your aquarium can maintain without large daily or seasonal swings.

Use appropriately sized heaters, cooling or ventilation, temperature monitoring and a plan for power interruptions. A backup heater controller or independent high-temperature alarm is worth considerably more than discovering a failed thermostat through bleached coral.

Maintain salinity near natural seawater—commonly about 34–36 ppt, or approximately 1.025–1.027 specific gravity when measured and calibrated correctly. An automatic top-off system helps replace evaporated freshwater, but it should have safeguards against both running dry and overfilling the aquarium.

Calibrate refractometers or conductivity probes with an appropriate standard. Top off with freshwater, not mixed saltwater, unless intentionally correcting salinity. Make corrections gradually unless an immediate hazard requires action.

Placement and spacing

Place Acropora where they receive suitable measured light and strong, changing flow—not automatically on the highest rock.

Before mounting a frag permanently, consider:

• Its current light acclimation stage
• Flow around the base and branch tips
• Future vertical and horizontal growth
• Shading from neighboring colonies
• Access for cleaning, inspection and fragging
• Distance from corals capable of stinging or overgrowing it

Leave several inches where practical and considerably more for fast-growing branching forms. Acropora encrust before or while developing branches, so the footprint may become permanent sooner than expected.

Avoid repeatedly moving a coral in search of instant polyp extension. Give it time to respond unless you see progressive tissue damage or another urgent warning sign.

Feeding Acropora

Acropora receive much of their energy from photosynthesis, but they are not sustained by light alone. Corals can capture plankton and particulate material, and they use dissolved nitrogen and phosphorus within the reef system.

In a well-fed aquarium with an appropriate fish population, direct feeding may not be necessary. Regular fish feeding supplies a broad background of nutrients and suspended material.

If you use a coral food:

• Choose a fine, appropriately sized product.
• Begin with a small amount.
• Keep enough water movement for food to remain suspended.
• Watch nitrate, phosphate, algae and water clarity.
• Increase only if the system can process the additional input.

Target or broadcast feeding can be useful, but more food is not automatically more growth. Dumping powder into a low-export system is still dumping powder into a low-export system.

Polyp extension can vary by coral, time of day, fish activity and flow. It is useful observational information, but not a standalone measurement of feeding success or health.

Frag arrival and acclimation

Prepare your quarantine container, dip supplies, clean rinse water, mounting materials and test equipment before opening the shipment.

When the order arrives:

1. Inspect the package and coral under white light. Photograph any visible damage immediately.
2. If the coral appears compromised, preserve the packaging and follow the Shipping & DOA Policy.
3. Keep the coral in reduced light during handling.
4. Equalize temperature as appropriate, then compare the shipping water’s salinity with the quarantine system.
5. Acclimate in a separate clean container based on the coral’s condition and the difference between the two water sources.
6. Do not pour shipping or dip water into the quarantine or display aquarium.
7. Inspect, dip and rinse the coral before quarantine.
8. Begin with reduced light and suitable flow, then acclimate toward the intended placement.

Do not force every shipment through the same timer. If transport water is badly degraded, extending exposure to it can be more harmful than a quicker transfer. Assess the coral and water rather than treating “drip for exactly X minutes” as a law.

Quarantine, pests and responsible dipping

Every Acropora should be inspected under white light and, ideally, quarantined in a separate stable system before entering the display.

Look closely at the coral, plug and exposed skeleton for:

• Acropora-eating flatworms and pale bite marks
• Golden-brown flatworm egg clusters
• Red bugs
• Unusual recession around the base
• Algae, vermetid snails and other hitchhikers
• Damaged, dying or suspicious tissue

Dips can remove or kill many mobile pests, but they are not a complete quarantine process. Acropora-eating flatworm eggs may survive treatment and must be found and removed manually. Repeat observation or treatment may be needed according to the pest’s life cycle and the dip protocol.

Use only a coral dip appropriate for Acropora and follow its current label exactly. Never mix dip products, improvise concentrations or add dip directly to the display. Use the protective equipment and ventilation specified by the manufacturer. Rinse the frag in clean quarantine-system water before transfer and discard all shipping, dip and rinse water safely.

A separate observation period of roughly two to four weeks is a useful baseline. Extend it when pests, eggs, tissue loss or other symptoms are found. The quarantine system itself must have stable temperature, salinity, light and flow; an unstable holding tank is not protection.

Why Acropora change color between reef systems

An Acropora frag may not look identical after moving to a different aquarium—even when it is healthy and its lineage is unchanged.

Visible color is influenced by:

• Light spectrum and intensity
• Photoperiod
• Host fluorescent proteins and chromoproteins
• Symbiotic algae density
• Nutrient availability
• Temperature and other environmental stress
• Viewing angle, camera settings and filters

A coral grown under one spectrum can become lighter, darker or emphasize different pigments after transfer. Some changes happen over weeks; complete acclimation and colony-level coloration can take months.

Compare progress photographs under the same lighting, white balance, filter and camera settings. Blue-light fluorescence is real, but it is not the same view your eyes receive under daylight. A new system may produce a different expression of the same coral without making either version fraudulent or unhealthy.

Color alone should not drive rapid adjustments. First determine whether tissue is intact, growth is continuing and the system is stable.

Common warning signs and troubleshooting

Warning sign	What it may indicate	First checks
General paling or bleaching	Abrupt light increase, elevated temperature, salinity change, nutrient limitation or other stress	Temperature history, salinity, recent lighting changes, nitrate and phosphate
Browning or dull color	Changed light, increased symbiont density, nutrient shift or normal acclimation	PAR and spectrum, nutrient trend, recent moves, growth
Tissue loss from the base or branch	Flow problems, pests, instability, damage, infection or shading	White-light inspection, alkalinity log, flow, temperature, neighboring corals
Rapid tissue loss	Severe acute stress, contamination, temperature event, major chemistry error or disease	Verify all critical measurements immediately; inspect other livestock and recent changes
Pale or damaged tips	Rapid growth, light stress, alkalinity instability, low nutrient availability or physical damage	Alkalinity trend, light history, nutrients and direct pump exposure
Reduced polyp extension	Flow, fish irritation, pests, light cycle, recent handling or chemistry changes	Observe day and night, inspect closely, review flow and recent changes
Bite-like pale spots or egg masses	Possible Acropora-eating flatworms	Isolate, inspect under white light, follow a verified quarantine and treatment protocol
Algae growing on white areas	Tissue is already absent from that area	Determine whether tissue loss is active and identify the underlying stress

A sensible troubleshooting order

1. Confirm the reading with a reliable test before correcting it.
2. Review temperature and salinity history.
3. Inspect the coral under white light, including the base and underside.
4. Check the alkalinity trend and dosing equipment.
5. Review nitrate and phosphate trends.
6. Confirm pumps, heaters, top-off and other life-support equipment are operating correctly.
7. Review recent lighting, flow, chemical, maintenance and livestock changes.
8. Change one variable at a time unless there is an immediate hazard.

Avoid dosing a collection of mystery remedies because a coral looked annoyed on Tuesday. A clear timeline of measurements and changes is usually more useful than another bottle.

Progressive tissue loss, pest evidence or a tank-wide response requires prompt action. Isolate affected pieces when practical and seek experienced help with clear white-light photographs and a complete parameter history.

Acropora care parameters at a glance

These are common captive operating zones, not universal requirements. Match changes to the coral’s source conditions, make adjustments gradually and observe the animal.

Factor	Practical starting reference
Care level	Advanced; best in a mature, demonstrably stable reef
Lighting	Source-dependent; many captive Acropora are kept around 200–450+ PAR after acclimation
Light acclimation	Begin below the intended intensity and increase gradually over several weeks
Flow	Strong, random and multidirectional without a constant direct blast
Alkalinity	Commonly 7–9 dKH; stability is more important than selecting one exact value
Calcium	Commonly 400–450 ppm
Magnesium	Commonly 1,250–1,400 ppm
Nitrate	Measurable and reasonably steady; many systems operate around 2–20 ppm
Phosphate	Measurable and reasonably steady; many systems operate around 0.03–0.15 ppm
Temperature	Commonly 76–81°F (24.5–27°C), with minimal daily variation
Salinity	Approximately 34–36 ppt; commonly 1.025–1.027 specific gravity
Feeding	Normal fish-derived nutrition plus optional restrained particulate feeding
Placement	Measured light, changing flow and room for the mature colony
Quarantine	Separate inspection and observation system; dipping does not reliably eliminate eggs

Frequently asked questions

Are Acropora hard to keep?

They are less forgiving than many soft corals and LPS, primarily because they respond poorly to rapid changes. A reef keeper who can maintain stable alkalinity, temperature, salinity, nutrients, lighting and flow can keep Acropora successfully without chasing exotic numbers.

How much PAR does Acropora need?

There is no single correct value. Many captive Acropora are kept around 200–450 PAR, while some colonies thrive outside that range. Learn the coral’s source conditions, measure your proposed placement and acclimate gradually.

Can Acropora get too much light?

Yes. A coral can be stressed by an abrupt increase even when the final intensity would be acceptable after acclimation. Paling, reduced extension and tissue damage following a lighting change warrant checking intensity, temperature, nutrients and flow.

How much flow is enough?

Enough to keep water moving around the whole coral, prevent debris from collecting and create changing polyp movement without pinning tissue in one direction. Evaluate flow at the coral rather than relying only on pump ratings or total turnover.

Do Acropora need to be fed?

They benefit from available nutrition, but direct target feeding is not always required. Fish feeding, dissolved nutrients and suspended particles may supply enough in a mature reef. Supplemental foods should be introduced conservatively and monitored through nutrient and algae trends.

Why is my Acropora turning brown?

Possible causes include a change in light, increased symbiotic algae density, nutrient changes or normal acclimation. Browning is not proof of one specific problem. Confirm growth, tissue condition, PAR and recent parameter trends before changing the system.

Why is my Acropora pale even though the PAR is correct?

PAR is only one part of the environment. Check whether the coral was acclimated, whether temperature or salinity changed and whether nitrate or phosphate has become unavailable. Spectrum, photoperiod, flow and alkalinity stability also matter.

Should I dip every new Acropora?

Inspection and an appropriate prophylactic dip are sensible risk-reduction measures, but dipping is not a substitute for quarantine. Follow the product label exactly and remember that many treatments do not kill pest eggs.

Can an Acropora recover from tissue loss?

Recovery is possible when healthy tissue remains and the underlying cause is corrected, but there is no guarantee. Determine whether loss is active, isolate the coral when appropriate and correct confirmed problems gradually. In fast-moving cases, experienced reef keepers may preserve unaffected branches as separate frags.

Can a beginner keep Acropora?

A disciplined beginner with a stable system, reliable testing and a quarantine process can succeed, but Acropora are poor “learn by accident” corals. Start after the aquarium’s biology and daily consumption are understood—not simply after a certain number of calendar months.