Methods for selectively depositing high quality epitaxial material include introducing pulses of a silicon-source containing vapor while maintaining a continuous etchant flow. Embodiments of the invention include handpieces that include a grip panel comprised of a friction-enhancing material to facilitate gripping of the handpiece by an operator. The liquid present in the partial packing material beds with their dry solids profile can be recycled in the recycling phase in one or more loops comprising one or more partial packing material beds. The regulator unit is configured to regulate respective fluid therein.