The longer I'm in the hobby, the less I like caulerpa. It can go sexual and make a mess, and can spread all over the display tank. I have not kept sargassum, so I am simply parroting what I have read. It is not supposed to be as good for nutrient export as some of the green macros, but is OK. I have been using chaetomorpha for about a year, and I am totally sold on it.
Algaebase is a great site for ID. Unfortunately, it's down for maintenance for the moment.
Algaebase is a great site for ID. Unfortunately, it's down for maintenance for the moment.