You want really low flow. They do not live anywhere near the surf. I have 2 giganteas and a haddoni....all personally collected....and the dozen or so others I have found are also found in lagoon areas attached to rocks buried in the sand or just above it. None of them are in water deeper than 3-4 feet. You can have great flow in the tank.....just make sure none of it is directed at the anemone. So basically, if their tentacles are flapping.....you have too much flow on them and they will definitely move. Once they find a spot where they feel their foot is fairly well protected, mine have not moved much at all. I am amazed at how well they have done. Here in Okinawa, MHs and T5s are something you can really only get if you order them from the states. I have mine in a 20 gallon and a 6 gallon tank with 2x20W T10s and they are doing fabulous. I replace the bulbs every 4 months. I have had them now for 15 months and one has almost outgrown the size I wanted.....I plan to bring them back with me next year.
Nice find and good luck.