Hi Keith,

Hmmm well although I've only been growing Kingies for nearly 2 years, I
think for starters it shouldn't be in rock/clay pebbles, those should
just be down the bottom of the pot to aid drainage.

I got the following information he
http://www.anos.org.au/cultivation/cultiv.htm

"To grow these orchids in pots you must provide a very open potting
medium. The bark will need to be clean and about 1/2" to 1" in size and
should be soaked for a week in water containing a spoonful of Dolomite
Lime, a spoonful of Chelated Iron and a spoonful of a high Nitrogen
fertiliser like Aquasol. After soaking, wash the bark in clean water
and you can then store it in a plastic garbage can or similar.

To pot up one of these orchids use the bark and clean stone pebbles,
about 1/4" to 1/2" in diameter, at the rate of 60% bark and 40%
pebbles. Make sure the base of the plant is above the mix.

Alternatively you can grow Dendrobium kingianum, as it is correctly
called, in the fork of a tree that does not lose its bark, eg. Fruit
Trees, Maples etc. Put some sphagnum moss over the roots after tying it
to the tree firmly. Water and fertilise with an organic fertiliser
regularly. Water every day and fertilise once to twice a week. This is
the case for potted or raft grown plants. Growing on a tree or other
exposed root method is called growing on a raft."

Another bit of info can be found he
http://www.orchidweb.com/dtl_spec.asp?PRecno=139

Hope you find those helpful. if you have any questions or comments
please feel free to contact me

Cheers,
Jo