I don't like to comment because I've only had a reef for two years, so yeah, very much still learning myself... but, I believe Hydnophora Corals are SPS and if so, not a good idea for a new reef tank, they have very specific requirements that a new tank just can't supply. As a a noob, I've found it best to buy my corals from sellers that offer lots of legit information about a specific coral along with the photo of the coral, that makes doing research before you buy much easier. My absolute favorite coral seller is Tidal Gardens, great info about corals on their web site and they have very informative videos on many specific corals on their YouTube channel, also, I haven't found cleaner corals anywhere and that's hugely important because hitchikers on corals is yet another complex and difficult subject and something you want to avoid as much as possible, especially in the begining. BTW, I don't have any conection to Tidal Gardens at all, that man just happens to run a very tight ship! There are other coral vendors that supply good information and corals, he's just my fav. You are so lucky to have found R2R, I have learned sooo much on here, I hope you have success AND fun with your tank!