Imagine that you are just stepping off a long inter-continental flight. As you step off you are walked through a long hallway with air that has a smooth gradient of temperature and pressure to carefully acclimate you to your new environment. Then once you reach the end of the Skywalk, you are hosed down and sprayed with all kinds of disinfecting agents, then you are allowed to be on your way.
This is kind of like the status quo for what is considered proper coral acclimation procedure, and professed to all new coral acquisitions and purchases. for some reason, somewhere along the way it became normal to at once treat our corals like delicate creatures and then blast them with noxious irritating agents.
In this scenario we carefully adjust the corals’ water to match the alkalinity, pH, temperature, & salinity of their eventual home, and then we give them a rough treatment of citric acid, iodine, pine oil and more to “cleanse” them from any potential pests and parasites they may carry. What is the sense in that?
We discussed it with Julian Sprung and he generally agrees:
“In general it is not necessary to drip acclimate corals or to be very precise about making the temperature adjustment (ie floating the bag). Temperature differences of 5 – 10 degrees F are not a problem for stony corals. Furthermore, stony corals that have become too cold (below 70 degrees F) or too hot (above 85 degrees F) in transit benefit from being transferred to water at a normal temperature (74 – 78 degrees F) without delay.
Xeniids are sensitive to temperature change, however. If Xenia is in the bag at 75 degrees and your tank is maintained at 82 degrees, then it may react negatively for several days. It won’t die, but it will look deflated. You can’t really acclimate it slowly to such a difference. It will react negatively even if you drip acclimate or float it to let the temperature change slowly.
The main thing I check is that the density of the water is more or less close. This is especially important for soft corals. Xeniids in particular do not appreciate a big change in density, but leather corals also may be stressed by a big drop or big increase in density. A change (in either direction) from say. 1.025 to 1.018 might be a problem but from 1.021 to 1.024 is not a problem. Stony corals are less sensitive to these changes. Acroporids may bleach if there is a drop in density of more than .005 points. Increases in density are less problematic.
Before introducing corals to the aquarium I dip corals in Revive, using water from the aquarium or the water from the bag the coral was transported in. “
By and large, most home hobbyists who buy a coral from the LFS or receive it in the mail from an online order should get the colonies into good moving water as soon as possible. Corals are passive creatures, their tissues create natural gradients between them and the outside environment, so acclimating corals is somewhat redundant.
As Julian pointed out, only in extreme cases of temperature or salinity differences, or with temperamental Xeniids, should you take a few minutes to acclimate your corals. But if you acquired your corals locally, chances are the water quality should be right in line with what you have in your own aquarium water.
As for dealing with pests and parasites, this should be done on a case by case basis. We like to “Don’t risk it, dip it”, but parasites of Euphyllia, Chalice corals, Scolymia, Acans and many others are all but unknown in the aquarium hobby. If you’re really that concerned about it, set up a coral holding tank that is separate from your display in which you can quickly get corals into good moving water, and observe for parasites, pests or disease before prophylactically knee-jerk-dipping corals into a caustic coral dip bath.
There’s plenty of cases where you want to pay special attention to the needs and specific parasites of a given coral species, but most of these treatments are for coral professionals to deal with on first import. So without further ado, by and large, this is how most home coral aquarists should acclimate their corals. We do this for 99% of our corals and can’t think of a single time when we saw a negative effect from just getting the coral into good and flowing water as fast as possible.