Before introducing corals into the tank, I dip everything in Coral RX. Double the recommended dosage and duration. I typically leave the coral in the original packaging with LFS water, add Coral RX into the bag and shake it vigorously for several seconds. I repeat last step after about ten minutes later and let it sit for another 10 minutes. After shaking the bag with the coral in it one more time, I remove it and place it in a container filled with tank water and leave it for a few minutes. As a final step, I inspect the container and coral/plugs/rocks closely for any undesirable parasites before introducing the corals into the tank. If I discover any, I will dip it one more time.
Note that dipping corals alone is not full proof. Even after introduction into the tank, I monitor the corals closely for health. Good polyp extension plus encrusting growth after about a week are good signs. Continued growth at the base and tips, and improved colouration over time is what I strive for. Any deterioration would be cause for concern requiring closer inspection, investigation and treatment, if necessary.