First, excuse my bad English, as I am French. I need help, because I have an algae invasion, and nobody knows what it is. Please look at provided pictures, and if you wish to use them on your website or elsewhere, its fine with me. This algae is rigid, grows in bouquet and his color is purple. When you pull it, she breaks into small pieces. Perhaps you have a name and predator for this algae?
St-Raphaël, Var, France
Thanks for your letter and from what I can see in the photos, you have low growing Galaxaura fastigiata, a calcified alga that has hard hollow cylindrical branches. There is nothing that I know of that eats this alga, except maybe a parrotfish, which would not be a good species for the corals in your aquarium. Beside just pruning as needed, there's no quick way to rid the system of it. Nevertheless, its somewhat nice looking if maintained in small amounts.
You can also visit my website at saltcorner.com where you can see other forms of algae on its 'Algae Page.' Go to my website, then open the 'Guest Articles' page to see it. My site has translation software, so you can read it in French.