They are very easy to propagate and they grow very very quickly. I started with 3 colonies (some of which were only 1-10 polyps on a single stalk, and now they've grown huge) and then got a 4th through a mistaken shipment. I have had problems with the sweepers, though, against, of all things, the other galaxea colonies. The easiest way to get one is to simply snap off a sinlge polyp and stick it in a hole in a rock. It will grow in no time, but watch out for the sweepers. I have heard they can be pruned back by simply cutting them off, but I don't think I trust that method too much (why would you damage the membrane of any lps and risk infection?). One of mine is within 6 inches of some xenia, a crocea clam, a toadstool, a devils hand leather, and some shrooms, and having the current blowing the sweepers away from these others is very effective.
By the way, if I solve my problem by moving one of the colonies, I'll try and snap off a couple of polyps and let them grow into a rock for you if you want. Like I said, you only need one polyp and it'll grow a new colony in no time at all.
[ January 07, 2002: Message edited by: davelin315 ]</p>