I just have what came with the tank it’s a simple intake that gets ran through sponge filters and a bunch of media the through a return pump and back into the tank through this dual nossle flow thingWhat do you have for providing water flow in the tank? An equipment list helps us know how to give advice too. Welcome to the club and reefing!
You usually want plate corals on the substrate since they like to inflate and scoot around a bit. The long tentacle varieties were on the more expert level in the past, so I'm not sure if they're improved recently or not.