Since you'll be shipping SPS corals, some tips:
Get them to slime up, rinse it off, repeat several times. The idea is to get all the slime out of them so it doesn't wind up in the bag. You can do this by simply pulling them out of the water for a few seconds, dunking them back in, and turkey basting.
Get large bags and float the corals. You can do this by getting a large chunk of styrofoam and rubber banding the rock the coral is on to the foam. If you can't do this, wrap the coral in a loose bag before placing it into the shipping bag.
