You know, I used to see xenia at Keiths (Aquatic Design) and just pine for it, wishing like crazy I could have some. Thanks for the kind words about my "steel" strength xenia. I believe it's a strong strain because it's tank raised (for many generations) and I ignore the whole tank most of the time, except for feeding, top off and cleaning the glass, which I feel I should do because it's in my office, not my home.
What has made my xenia varieties (now I have two kinds, a white kind that's feathery and doesn't pulse) grow is the following recipe:
1. Keep it high in the tank unless you have MH, which may be too much light. (I have 600 watts of PC lighting currently).
2. Dose the tank weekly with Lugol's solution, which is a special blend of iodine and iodide.
3. Feed the tank with DT's three times a week per the instructions on the bottle.
4. If you have an eco-system like I do, don't use a skimmer... xenia like "dirty" water from what I can tell. Read #5 for proof...
5. If you get the urge to do a water change, take a nap instead. I do very, very few water changes to the 150 and the 55 I had before that for 10 years. Four or five 10% water changes per calendar year. I know this sounds absurd, but everything's growing and happy, so its hard to argue with. But, I believe I must also add that I have a balanced bio-load and probably 200 pounds of live rock.
I have found that this recipe is also keeping my hard corals, soft corals, fish, inverts, LPS and SPS quite happy and growing. Problem with the xenia is that it grows fast and begins to encroach on the light and physical space of my frags and enormous candy cane coral (which resembles a human brain in size and shape now).