As a (retired) respiratory therapist, I was always taught to EMPTY a heated humidifier and refill from scratch, rather than top it off (unless it was a closed system such an F&P or Concha). So, dutifully, after each use I would drain the water out completely after the "cleaning" cycle. I have contacted the company several times over the past two plus years, and have even had it replaced under warranty once. Despite MANY short cycles (with water still visible in the reservoir) then going to "cleaning", I persisted, dutifully waiting till the cleaning cycle ended, dumping the residual water, refilling from scratch and the short cycle repeated. This was extremely frustrating, AND used up a HECK of a lot of precious water. A week ago, after repeating this little comedy of frustration several times, I called product support, and this time, probably by accident, I asked the right question: "Do I empty out the residual water after the cleaning cycle is through, or at the start of the cleaning cycle?" This triggered a response I had not heard or read before: Do NOT empty the residual water if you plan to use the Mypurmist in the next day or so. If you have emptied the water out and want to use it days or months later, fill the water reservoir and let it sit for an hour or more to reprime the fill mechanism before turning it on. Since using this approach, it has worked really well with no short cycles.