I found some really nice macro algae growing out on Montauk this year. I have a few pieces in my reef since the beginning of the summer and it is growing well. I can get all I want (in the summer) and it's free. It grows on limpet shells and when the limpet dies it floats to shore. Or I can collect them with SCUBA. It seems to grow about 12". I have pictures but I have dial up service and I can't post them. I can E mail them if you would like to see them or if you can post them for me. In the spring I hope to collect a bunch of it. So far my tangs, snails, crabs, lettuce nudibranch and algae bleeny do not eat it.