Acclimation is the process by which a coral, fish, or invertebrate is transferred successfully from the shipping bag of water into your home aquarium.  Why is acclimation important?  Because marine fish,  corals, shrimps, anemones, and other forms of ocean life are used to stability, and any abrupt change to their environment could lead to stress, disease, or even death.  While there are many opinions on how to properly acclimate your new arrivals, the one thing most hobbyists can agree on is that it is absolutely necessary to spend some time acclimating anything that you place into your aquarium.

Temperature, pH and ammonia levels often go awry during shipping and long duration in a closed bag.  In addition, the hobbyist must be concerned with salinity differences between the shipping water and their aquarium water.   How does the reef hobbyist deal with this? Acclimation.  

1) Temperature-  The proper way to slowly adjust the temperature of your newly arrived coral, fish, or invertebrate is to float the bag in your existing aquarium water under dim lighting conditions only.  Do NOT float a bag under a set of intense and hot lights!!  This will cause the water in the bag to heat up too rapidly, and can shock the new arrival due to the intensity of the light at the water's surface.  The best way to temperature acclimate is in a sump, refugium, or main tank with the lights out (or turned very dim if possible).  Do not open the bag and start exchanging or dripping until the temperatures are equal inside the bag and inside the aquarium.

2) pH-  The pH often drops during shipping, due to fish respiration and waste released into the shipping water.  Acclimation will bring the pH in the bag gradually up to the pH level of your aquarium.  The proper pH for your saltwater aquarium is 8.0-8.4, the proper pH for your freshwater aquarium is 7.0.  The higher your tank pH the longer you should acclimate, but don't generally exceed 60 minutes. On average, this process should last 20-45 minutes.  It's also important as you bring the pH up to add ammonia neutralizer, because as the ph increases in the bag, so does the toxicity of the ammonia.  See below. 

3) Ammonia-  Ammonia builds up in the shipping water due to fish and invertebrate waste in the bag. The lower pH in the shipping bag renders the ammonia less toxic.  After temperature acclimation, we recommend a few drops of a commercial ammonia neutralizer, such as amquel, be added to the bag water.  Once the neutralizer is added, begin adding tank water to the bag and removing shipping water gradually until you have exchanged at least 75% of the water, or proceed with drip acclimation at this time.  So as you acclimate the pH will rise back up to tank levels and the ammonia will be diluted out.  Never acclimate without ammonia neutralizer because as the pH in the bag rises, the ammonia in the bag becomes more toxic and will cause excess respiratory stress to the fish / invertebrate.

4) Salinity- Salinity or specific gravity, the amount of salt contained in the seawater, will generally not fluctuate during shipping.  However, acclimation is very important to ease the transition from the bag salinity to the aquarium salinity.  We generally recommend at least 10-15 minutes of acclimation for every point difference between the two salinities.  Example:  The bag salinity is 1.026, the tank salinity is 1.022, that's a 4-point difference in salinity, therefore acclimate for 40-60 minutes.  Salinity of our shipping water will generally run 1.018-1.020 for fish, and 1.023-1.025 for corals & inverts.  We recommend testing the water upon arrival with a reliable refactometer, and not placing the fish or coral into the tank until the salinities are equal.


Procedures & Acclimation How to's

Now that you understand the basic reasons for acclimating, Aqua Dreams recommends two methods: The drip or the float/exchange.  With the drip method, a length of airline tubing is used to slowly "drip" tank water into the bag, while removing bag water gradually during the drip process.  We recommend a piece of airline tubing with a flow control valve on one end to control the drip rate.  The original bag can be used as the drip receptacle or a clean container of your choice.  Be sure to place something over the top of the container to contain jumpy fish if using this method.  We recommend dripping for 30-45 minutes, while gradually removing water, until the original water has been mostly replaced with tank water.  The float/exchange method is where the bag is kept floating under dim lights, while slowly adding aquarium water to the bag and removing bag water every few minutes.  Dispose of bag / shipping water, never add it to your display tank.  This method requires you to loosely re-tie the bag each time you do an exchange- do not let the bag go "flat", keep an air-pocket in the top of the bag at all times while using the float/exchange method.  Once you have exchanged most of the water in the bag you can place the fish / invertebrate into the display tank and dispose of the bag water.

    The main advantage of the drip method is the exchange of water is more gradual.  The disadvantage to the drip method is the temperature in the drip receptacle or bag can drop since its' no longer floating in the aquarium.  The main advantage of the float/exchange method is constant temperature equilibrium.  To combat temperature drop while drip-acclimating, some hobbyists place the drip receptacle container in a larger tray or bucket with tank-temperature water surrounding it to maintain temp while drip acclimating in a room that is less than 76 degrees.   So while both methods have their advantages and disadvantages, the hobbyist must decide what works best for them.  Always dispose of remaining shipping bag water (never add it to the display tank), with either method chosen.  During periods of extreme cold, i's often a good idea to open the shipping box in a room-temperature environment and let the bags slowly warm up for 1-2 hours before floating, so as not to bring the temperature up "too quickly"