How to Acclimate Corals | Correct Procedures for Drip Acclimation and Temperature Matching
Explains methods for acclimating corals (drip acclimation) when introducing them to a new aquarium tank. Introduction to temperature matching and drip acclimation procedures, time guidelines, and important points to observe after introduction.
Key Takeaways
Explains methods for acclimating corals (drip acclimation) when introducing them to a new aquarium tank. Introduction to temperature matching and drip acclimation procedures, time guidelines, and important points to observe after introduction.
What is Coral Acclimation? Why is it Necessary?
When purchasing corals and introducing them to your home aquarium, the one step you absolutely cannot skip is "acclimation." Acclimation is the process of gradually bringing the water parameters of the shipping bag closer to those of your own aquarium. Neglecting this step exposes the corals to sudden environmental changes, causing serious damage.
Corals are even more sensitive to water quality changes than tropical fish. During transport, CO₂ accumulates in the bag, and it is not uncommon for pH to drop significantly. Additionally, depending on the season, water temperature may fluctuate during transport, creating a temperature difference of 5°C or more between the shipping bag and the tank. The specific gravity (salinity) may also differ slightly between the breeder's husbandry environment and your tank.
When these parameters change suddenly, coral cells can undergo osmotic shock, and the symbiotic zooxanthellae may leave the coral, initiating "bleaching." Although acclimation is a time-consuming process, it is the first and most important step in keeping corals healthy and long-lived.
Preparation and Checklist Before Acclimation
Before beginning acclimation, preparing and confirming several points will ensure a smooth process.
Gather Necessary Equipment
- Clean bucket (free from tank water)
- Air tubing (for drip acclimation)
- Thermometer
- Hydrometer or specific gravity meter (if available)
- Stopwatch or smartphone timer
If you're uncertain about measuring and managing specific gravity, reviewing equipment selection options in the Complete Guide to Reef Tank Specific Gravity (Salinity) Management will help put your mind at ease.
Obtain Water Quality Information from the Breeder
If possible, confirm the "packing water temperature," "specific gravity," and "pH" with the breeder from whom you purchased the corals. Knowing these values allows you to assess the differences from your tank and adjust the acclimation time and care accordingly. Especially if the specific gravity difference is large, it is recommended to spend more time than usual on acclimation. The Coral Shipping and Transport Guide also provides useful information on the packing and shipping methods that affect the condition at arrival.
Check Lighting and Water Flow
Corals are sensitive to strong light and water flow immediately after introduction. Before acclimation, consider setting your tank lighting to a lower level or positioning the corals in a darker area for a while after introduction.
Temperature Matching Procedure
The first step in acclimation is "temperature matching." This is done before opening the bag.
- Float the received corals in the bag as-is on the water surface without opening it.
- Leave it for 15–20 minutes to allow the water temperature in the bag to approach the tank water temperature.
- Check the temperature of the bag's exterior and the tank with a thermometer, and proceed to the next step once the difference is 1°C or less.
When performing temperature matching, be careful not to let the mouth of the bag sink into the water. If the bag tends to sink, you can secure it to the tank's edge with a clip or float it in a bucket containing a small amount of tank water.
Drip Acclimation Procedure
Once temperature matching is complete, proceed to the main "drip acclimation" method. This involves gradually adding tank water drop-by-drop to the bag water, allowing water parameters to slowly approach those of your tank.
Basic Procedure
- Open the bag and transfer the corals along with the bag water to a bucket. The key point is not to discard the bag water—this water serves as your base.
- Secure one end of the air tubing in the tank and let the other end hang into the bucket. Use the air tubing to guide tank water into the bucket using the siphon principle.
- Tie a knot in the middle of the air tubing to adjust the flow rate to approximately "1–2 drops per second." If the flow is too fast, it defeats the purpose, so be patient and keep it fine. If you have a valve for air tubing, you can make more precise adjustments.
- Continue dripping until the bucket's water volume doubles (approximately 30–60 minutes). Taking your time allows the water parameters to gradually approach those of your tank.
- Discard half the bucket water and drip again until the volume doubles (for extra care). For sensitive species such as LPS (large polyp stony corals) or delicate SPS (small polyp stony/Acropora-type corals), repeating this step twice provides extra assurance.
- Remove the corals by hand or net and place them in their intended location in the tank. Do not add the bucket water to the tank—discard it instead. Transport water may contain pathogens or parasites.
Key Points for Drip Acclimation
- During the process, place the bucket in a dark area or cover it with a towel to reduce stress
- Adding aeration to the bucket helps recover pH that may have dropped during transport
- Choose a bucket with adequate size to prevent water from overflowing
Post-Introduction Care and Observation Points
After acclimation is complete and the corals are placed in the tank, it is important to continue observing them carefully for some time.
First Week Management
- Start with dimmer lighting: Exposing corals to strong light immediately after introduction causes light stress. Start with approximately half your normal lighting duration and gradually return to full intensity over 3–5 days.
- Avoid feeding: No feeding is necessary during the first week to reduce strain on the digestive system.
- Maintain gentle water flow: Overly strong water flow can damage polyps.
Is This Normal or Abnormal?
| Condition | Assessment |
|---|---|
| Polyps retracted 24–48 hours after introduction | Normal (adapting to new environment) |
| Polyps gradually begin to open after 3–5 days | Sign of healthy progress |
| Polyps remain closed for over a week | Concerning. Review placement, water flow, and water quality |
| Producing white slime | Stress response. Reduce water flow and light intensity |
| Tissue melting (RTN/STN) | Requires immediate action. Isolate to prevent infection spread |
During the first few days after introduction, minimize touching the tank and focus on calm observation—this is the fastest path to recovery. For detailed information on how to handle tissue melting symptoms, see Coral Diseases and Treatment (RTN, STN, BJD).
The most important aspect of acclimation is taking sufficient time. SPS corals are particularly sensitive to rapid water quality changes, so a drip acclimation process lasting at least 2–3 hours is recommended. Additionally, be mindful of water temperature changes during acclimation. During winter, use a container with a heater or perform the acclimation in a temperature-controlled room with air conditioning.
BreederDirect's Reliable and Safe System
At BreederDirect, you can purchase corals directly from breeders. Since we bypass the middleman shop, corals are not stored in long-term stock conditions but are shipped directly in the breeder's stable husbandry water.
Additionally, many BreederDirect breeders share water quality information such as packing water temperature and specific gravity, making it easier for the recipient to plan their acclimation. Even if you're thinking "I'm purchasing corals for the first time and I'm worried about the acclimation method," you can consult directly with the breeder via message. You often receive accurate advice from experienced breeders, and the environment is set up so beginners can confidently take on this challenge.
The first step in coral husbandry begins with proper acclimation. Taking your time and working carefully is the surest path to long-term success.