Previously, it has been shown that administration of 5 mL of 7% HS QID by the Pari LC Star leads to a significant improvement in the lung function in CF patients. The investigators estimate that this dosing regimen deposits ~400 mg of NaCl per day but requires four ~18 minute administrations (deposition rate = 5.8 mg/min). Although HS is generally well tolerated in the CF population, intolerance does occur and is largely related to the rate of NaCl delivery to the oropharynx and airway surfaces. As nebulizer devices capable of administering aerosols through a nasal cannula are not currently available, Parion Sciences has designed a customized nebulizer spacer that entrains the aerosol from an approved and marketed Aerogen Aeroneb Pro vibrating mesh nebulizer into a nasal cannula without significant "rain out" or dripping from the cannula. The tPAD system being utilized has an output rate of ~50 ul/min, and so emits ~3.5 mg/min of NaCl and deposits ~1.3 mg/min in the lung (38% deposition efficiency). If used overnight for 8 hours, the investigators estimate that 640 mg NaCl will be deposited in the lung. Therefore, the investigators project that this novel administration system has the capacity to deliver approximately 50% greater mass of NaCl to the lung when used overnight, compared to 4 times a day treatment with a standard oral nebulizer, thereby potentially increasing efficacy. However, because the lung deposition rate is less than 25% that of the standard oral nebulizer, the investigators anticipate that the tPAD will also be better tolerated and will eliminate the need for daytime HS treatments. In this study, the investigators will explore the safety, tolerability and effect on mucociliary and absorptive clearance rates of a 7% HS solution administered continuously overnight via the transnasal route.