At Community Works we had a 5 gallon setup with a tap and would refill it continually, distilled of course, and redo it every week 10 days or so and I know that untill the managment change in the San Diego lemon Grove Wiggimore center mabey 6 or 8 years ago ( I think they changed a few things), the rejuvilac was being pumped out by the gallons and at the sunday eve dinner I had thought about bringing a container and filling it up. I think most problems are the heat. Unlike yogurt the temp must not go too much above 80 some degrees. I make it irregularly but unless I dont pay attention to it, its pretty straighforward and so good.
And IC, in the CZ archives there are a few threads where some started to share about reality accsesories, your fungus topic, and the younger group, not chronological age that is, started to really become upset, so the threads got a bit sticky.