that and also had no problems when it came into contact (for a week), with a porities coral . i had a rbta which did all kinds of strange things . it burnt welts into the corals within minutes of touching them . it would drop those tentacles leaving them on the coral to continue killing , they would deflate and couldn't be removed . i could go on but i have other things to do now suffice to say to me they're overgrown aiptasias . some look very nice and others look like a bunch of earth worms and they often go back and forth for no apparent reason . with the sebae , given the proper conditions , the large volume of h20 in your 180 will provide a good margin of error .