Phalaenopsis Orchids, unlike most orchids, prefer a slightly moist media at all times. Phals have no water storage facility, such as psuedobulbs, to retain water. Phals inhabit, in the wild, a constantly moist environment. So, In straight bark mixes, higher watering frequency is necessary to maintain constant slight moisture at their roots. Phals do not like dry roots, their motto: "I dry, I die", so their media mixture should always contain some moisture retainers, while maintaining an open, airy media, hence coconut chunks. Drains well, while retaining adequate moisture for Phalaenopsis. CoCo Nut chunks retain water, while resisting material breakdown Reduce watering frequency, while retaining moisture at the roots.