How to Drip Acclimate Corals: Temperature and Salinity Matching

Corals may not swim, but they are just as sensitive to sudden environmental changes as fish. This drip acclimate corals guide covers the precise steps for matching temperature, salinity, and pH before introducing new specimens to your reef. At Gensou Aquascaping Singapore, we have handled thousands of coral shipments over more than 20 years, and proper acclimation consistently separates thriving additions from mysterious losses.

Why Corals Need Acclimation

Corals are sessile invertebrates that cannot flee unfavourable conditions. A sudden shift of even 0.003 in specific gravity or 1.5°C in temperature can trigger mucus overproduction, polyp retraction, or tissue recession. Shipping bags accumulate carbon dioxide over transit, lowering pH to as low as 7.2. Dumping a coral directly into 8.1 pH water causes a rapid ammonia toxicity spike from the ammonium already dissolved in the bag. Gradual acclimation avoids all of these shocks.

What You Need

• A clean bucket or container (3 to 5 litres)
• Airline tubing with a control valve or loose knot
• A small cup or turkey baster for overflow removal
• A refractometer and thermometer
• Coral dip solution (iodine-based or proprietary)

All of these items are available at marine shops around Serangoon North Avenue 1 or online via Shopee for well under $30 SGD total.

Step-by-Step Drip Acclimation

Float the sealed bag in your sump or a separate container of tank water for 15 minutes to equalise temperature. Then open the bag and pour the coral and its water into your clean bucket. Set up the airline tubing as a siphon from your display or sump into the bucket, adjusting the valve until you get roughly two to three drips per second.

Let the drip run until the water volume in the bucket has doubled — this typically takes 30 to 45 minutes. Discard half the bucket water and repeat the process once more. By the end, the bucket water should closely match your tank’s salinity (1.025 to 1.026 specific gravity) and temperature (25 to 26°C for most reef setups in Singapore).

Temperature and Salinity Matching Tips

Use your refractometer to test both the bag water and your tank water before you begin. If the salinity gap is greater than 0.004 specific gravity, extend the drip time or add a third round. Temperature matching is usually straightforward in Singapore’s warm climate — bags shipped locally rarely drop below 24°C. For corals arriving via air freight from overseas, the temperature gap may be larger, so allow extra floating time before opening.

The Coral Dip Step

After acclimation and before placing the coral in your display, a brief dip in a coral-safe solution removes hitchhikers such as flatworms, nudibranchs, and acropora-eating bugs. Mix the dip according to the manufacturer’s instructions using tank water, immerse the coral for five to ten minutes, and gently agitate. Inspect the dip water for pests — you may be surprised by what falls off even seemingly clean frags.

When to Skip Drip Acclimation

Some experienced reefers prefer a modified float-and-transfer method for SPS corals, arguing that prolonged exposure to degraded bag water causes more harm than a quick transfer. If the bag water tests at the same salinity and temperature as your tank, a 15-minute float followed by a coral dip and direct placement is reasonable. However, when parameters differ significantly — common with online purchases shipped across Singapore or from overseas — drip acclimation remains the safer choice.

Post-Acclimation Placement

Place newly acclimated corals in a lower-light, lower-flow area of your tank for the first three to five days. This lets them recover from transit stress and adjust to your specific lighting spectrum. Gradually move them to their permanent position over one to two weeks. Watch for signs of stress such as excessive mucus, bleaching, or failure to open polyps within 48 hours.

Related Reading

How to Dip Corals Before Adding to Your Reef

How to Acclimate Marine Fish: Drip Method

First Corals for Beginners Reef Tank