Shoot, that's easy to fix! Scrape off the back wall with a razor, throw in a few Mexican turbo snails, and you're set! With such a new tank, and such small corals, I don't think you need to be dosing anything. Make sure you're feeding throughout the day, and do water changes. If you're N and P are too low, go longer in between changes.
I've stopped water changes on my 120g. Haven't done one in the past few months. Phosphate finally got up, and Nitrate is slowing rising (along with dosing Neo Nitro). Switched to Tropic Marin powdered All for Reef due to me not doing water changes as much anymore.