There's several different "camps" on this topic. Some of us float, dip, drop (float the bag, dip for pests, put it in the tank) while others of us dip, drip, float. A lot of people also will set up a coral QT tank which can help eliminate the risk from unseen eggs. Typically, they'll match the water from the seller as closely as possible, float, dip, drop and watch for a week or two for any pests.