I have been trouble finding distilled water for my CPAP on a regular basis. The price has gone up 15% this year but the worst part is the supply is sporadic. I decided to try this distiller b/c the price was right. Indeed it was very affordable compared to many other models. I followed directions and within less than 3 1/2 hours I had just shy of a gallon of distilled water. I did sprinkle some of the citric acid "detergent" in the tank, right after emptying the distillate. It dissolved the residue from the minerals that collected at the bottom of the tank. It was a simple process. And though I stayed home and checked periodically to make sure it wasn't running dry, it DID shut off automatically. I definitely recommend this Vevor water distiller.