I have had this problem too. It is a great indicator you need to lay off watering. You can actually use the sticks to tell you when to water and when not to water. If the part in the medium is darker than the rest when it is pulled out, you dont need to water. If it is the same colour as the rest of the stake, water it.
I always water my Phal when the top 3rd of the medium looks dry. They grow quite hapily like that.