I have a mini Phal that I had originally potted in bark mix in a slotted pot, but it wasn't doing well at all.
So I dumped the bark and replaced it with Viastone clay aggregate, and the 'pan' its sitting in is the bottom of a small water bottle. I did this back on August 29th, 2016.
I keep the water topped off at around one inch, and this little one is doing great. She's even put out a new leaf since!