I used to distill water for quite a few things in my house. Like brewing coffee I c pep device and pet water. So I have produced quite a bit of distilled water with this device and it is still working very well. I have used the recommended acid that came with it to clean it as well as cleanings between acid treatments with just white vinegar. It gets a fairly decent build up in the bottom. Just leave the top off and boil some white vinegar and water in it for thirty minutes, and ninety percent of the buildup will break loose and wash away. A little bit of remaining residue. You're just leave and on the next cleaning. It'll get it or doesn't get it, but if you've got 90 - 95% of it gone, it'll work just fine.
Willie Carrot 
