So, trumpet coral then hair algae.
Are you feeding your trumpet/candy cane? I've found mine LOVES to be fed, definately after hours when its feelers come out, but also during day if I put tiny pellets or very very finely chopped up thawed foods (have to have pumps off so food doesn't float off... night time is better so fish don't steal its food. Mine has so many heads in the colony its bigger than a softball, but it only got that way from targetted feedings. You can also mix Reef Roids or any of those other powders into thick paste, but then I had problems getting the paste to hold together all the way down to my trumpet colony (which was down to just a few heads).
Hair algae. Every water change, pull out the rocks, scrub them, rinse them with old tank water (you were tossing it out anyhow) and put the rocks back in. I found toothbrush too soft, scrub brush head too big, and so using a scrub brush's stolen bristles cut off with an exacto knife, I made my own flexible scrub brush. Scrub, scrub, scrub.
Light, nitrate and phosphates are fuel for green hair algae. Eliminate natural sunlight and figure out what you can do to reduce your nitrate and phosphate numbers.
In time, you WILL get to the other side of this.
Hang in there!