Hello, BigGreenLeaf -
I' still a newbie so not your best bet for advice on a growing medium - though what I've learned from OB is that the best substrate is the one that works for YOU, according to your growing conditions. I'm in sw England, so everything's mostly relatively moderate, grow space is in front of nw window - glass double door, actually, & orchids seem happy. Use medium orchiata straight, although cut 50/50 with sphag if repotting purchases grown in moss. Miss Flower's right though - pure sphag not a good choice, although I'm sure there are growers who swear by it. In order to find out what works for you, you should perhaps experiment. This will mean buying more Phals. A LOT more Phals. I started off with about four 18 months ago - now approaching the 30 mark. Not that I have an addictive personality or anything ... Have lost (killed) 3 - always v. sad.
Another thing I learned on OB is that Phals are tough little beauties, very forgiving. Two of my Phals I lost through fidgeting, poking, bothering and generally worrying them to death.
As for your shamrock - is it green or purple? I've had a purple false shamrock for ~10 years now. Google "oxalis triangularis" or "oxalis triangularis green" and you'll find lots of info!

Welcome to Orchid Board.

Clay balls and moss will work. Anything works if you adapt your watering to what you have. I myself prefer medium bark chunks mixed with moss and loosely potted in a clear pot with good air and drainage holes. Since you are going to an orchid show next weekend, you should be able to find some bark or a good mix of moss, perlite and bark. If Forest View is there (and they always are) they sell small bags of it. Phal. roots like to get nice and wet when watered but then get nearly dry right to the bottom before being watered again. I like the clear pots because you can see into the pot and the roots somewhat. also using the skewer method that is often mentioned here has helped many people, including myself to stop over watering their plants. Just get a bamboo kebab skewer and insert down into the pot near the centre where most moisture is retained. Leave it there and pull it out to see how wet it is before watering. If it is wet, its not time to water. barely damp or dry it is time to water.

There is a sticky thread in the beginners forum called The Phal Abuse Stops Here which is worth browsing thru as it answers pretty well any question on Phal culture and problems that you could think of.

Also consider joining your local orchid society as you will have a wealth of knowledge and like minded orchid growers to get to know. You should be able to get info on that while at the show and talk to many of the members :).