These are non-photosynthetic corals and are difficult to care for. They seem to be more sensitive to nitrates and alk swings than other soft corals. Some are collected from deeper waters and don't fare well at the warmer temps of most reef tanks. They need frequent feedings, which it sounds like you're doing, but unless the polyps are extended before adding food, the coral won't capture any of it. So best not to feed until it opens up (unless you're trying to feed other corals).
In the wild, I have most often observed these corals on deeper ledges and reef walls exposed to pretty strong currents, so good water flow (but not direct jets) are recommended.
Also, I noticed you placed the coral at the top of your reef where light is the highest. Since they don't need light, this can actually promote the growth of nuisance algae on the coral, which is obviously not good.
Not an easy coral. Best of luck with it.