When should I water this phal?

[JKeys]

I repotted this phal with a few small, stubby roots into a four inch pot, the only pot it would fit in. The pot is called an oxygen core pot. It has this black core, then space, then a plastic clear pot.

I watered about 4 - 5 days ago, and the top layer of sphag is completely dry. However, after two inches, it is slightly damp. I can't fell down to the bottom of the pot, but there is some condensation on the plastic pot. The roots don't extend far down - only about 2 and a half inches. Should I water it, or wait?