I use a lot of distilled water, not for just drinking, but also for my bipap machine. It has always bothered me how many plastic jugs I throw away (there is no recycling where I live) and with the price of water going up, plus the availability of said water becoming scarce, I thought it was high time I bought a Distiller. (Side point: I also bought a TDS water tester to check the purity of what was coming from it - https://a.co/d/eHzusye )I ran both the 1st liter batch with the included citric acid as recommended in the user manual and the first gallon and threw them both away as suggested. Now, I don't know if my reasoning is correct about this next part, but I feel like I wasted that first filter that was already in position. When I was about to run my next batch of "keeper water," I decided to toss the filter. My reasoning was that even though those first two batches were distilled, and even though I didn't use the TDS tester on them, the purity of the water was most assuredly compromised, so with my official "keeper water" I started with a fresh filter. (Side point: before you use a new filter, always rinse it free from any charcoal dust that may be lingering in it - I use distilled water to do this since I do not want tap water impurities mixed in - right or wrong, I don't know. It just seemed logical to me.)With that first gallon of "throw away water," I accidently let the reservoir run dry. I meant to stop it in time so that the gunk from the tap water wouldn't adhere to the bottom, but to my surprise, 3.5 hours after I started the process, it was finished. I think the manual said 3.5 hours, but for some reason I kept thinking the entire process took 4 hours - nope - 3.5 meant 3.5.I used distilled white vinegar to get the caked on gunk off of the sides and bottom along with a paper towel. I should have let it soak for a bit before attempting this clean up as it really was baked on.Then it was time for my "keeper gallon." As per another reviewers suggestion, I