Whether you are adding hard stony corals whether they are Large Polyp Stonies (aka LPS Corals) or Small Polyp Stony Corals (aka SPS Corals) or Soft Corals such as Zoanthids or Mushrooms, it is highly recommended to acclimate the corals from the bag of water they were in to your water.
Acclimating corals is always recommended to reduce further shock to the coral. Many advanced aquarists & respected authors encourage the use of quarantine tanks for corals in the same way fish should be quarantined. If this is feasible it can reduce your headaches should there be a problem. The only issue I have personally experienced with QT is with a smaller system, water parameters can be harder to balance.
When acclimating, you are gradually allowing the coral to adjust to the new water parameters. The three which create the biggest problems are pH, salinity and temperature.
First, put sealed bag into the top of your system (either display tank or QT). After approximately 15-30 minutes open bag and beginning adding .25-.5 cup of tank water to bag.
NEVER ALLOW BAG WATER TO ENTER YOUR TANK.
CORAL CAN EXCRETE TOXIC CHEMICALS AND CAUSE DEATH AND DESTRUCTION TO YOUR SYSTEM!
Second, after adding water to bag approximately 5 times over 1-1.5 hours, gently remove coral from bag and place in system. Discard water and place coral into recommended zone. If coral is recommended to reside in an area of med-high light, dim lights or run actinic lighting only during this initial introduction period. Remember- 24-36 hours of travel, change in water, touch by humans, new tank, new roommates, bright blinding light! It would be enough for me to retract for days and stop eating.
Third, during the course of the next 2-3 days, many advanced aquarists reduce the hours/intensity of the system. This allows the coral to gradually grow accustomed to the lighting. Remember if the coral is photosynthetic it MUST have lighting. If lighting is not provided, the corals energy needs will not be met! This will cause the coral to “employ” additional staff members of internal algae (zooxanthellae), increasing the brown pigmentation of the coral, hence the change in color you may have seen in corals not properly housed.
All prices are in USD