I use NO carbon and add 5 drops of Iodine each day.
I also add 3 drops each of Kent essential elements, coral-vite,
strontium and 2 drops of combisan.
Once a week I add at least 1/4 tsp of Mg.
I drip 2 cups of kalkwasser each evening, and
add 1 tsp each of B-Ionic #1 and B-Ionic #2 each morning.

I still have not found the secret to growing xenia.