Dom,

Yowza! Six years is an awful long time for a Phal to live in the same
medium. If the medium is organic (i.e. bark or moss), it is way far gone.

Get thee to your potting table a.s.a.p. I'm guessing that the roots are in
trouble. What you use for medium will depend upon your tendency to water
(often or seldom) and your growing conditions. I use Aliflor for most of my
Phals, but I grow outdoors in a humid environment. Indoors, you may want
something that will hold more moisture.

Look at these sites for information and links. The link to orchid lady's
repotting page is not working for me right now, but it will come back up.

http://www.orchidexchange.com/advice.htm
http://www.firstrays.com
http://orchidlady.com
http://www.orchidlady.com/pages/repotting.html

If you need more information, don't hesitate to ask.

Diana