You should make a little post bought those guys. You seem to be an expert on them. Im currious personally. How hardy are they? How many do you need per tank size? Do they eat anything else? Do they just die after they finish? Other fish in the reef find them tasty?
Someday if I have the time I might do a post. They are surprisingly hardy. Remember they eat aiptasia and aiptasia usually grow when your water quality deteriorates. Also I pull them out of my filter sock every time I clean it. They look like little cream colored blobs (not having eaten for a week) all beat up with half of their cerata missing. I pick them out and feed them an aiptasia and within a few days they are good to go. I would say greater than 80% survive the filter sock experience.
I have heard 1 for every 10 gals, but I recommend putting them in your sump (at least 3) and rotating your rock through there. As you rotate your rock they lay egg strands on it which go back into your display tank and hatch. Soon you have a healthy colony and your aiptasia start to disappear.