dahlia_guy, that would depend on conditions: temperature, light, humidity, air movement. The roots of Phals should dry off slightly between waterings, and how fast that happens completely depends on where you're keeping the plant. You may only need to water every two or three days. If the roots are sandwiched in between 2 thick layers of fiber, they'll stay moist longer. If they're on top of the fiber, they'll dry faster. Go with what the plant's moisture status is, instead of trying to set a schedule based on time.
I'll bet the plant looks good inside that coconut shell!