Thanks very much for your response, ChicagoGranny. What full-face mask do you use? For the last 18 months, I have been using a ResMed AirFit F30i ( https://www.resmed.com/en-us/sleep-apnea/cpap-parts-support/sleep-apnea-full-products-list/cpap-masks/airfit-f30i/ ) Thanks for that info, that looks l...