1. Distilled Water And baking soda. 1 tspn per cell full.
2. I have been running mine for a long time. I back up My work and if the cell fails I will replace. I will offer this for 1 year. Discoloration of the water and steel is normal.
3. I think its just under a quart of water. I have the same water I had in it about a month ago. It is supposed to last 80 hours of being on. I can Show you how to make a way to check it, without having to open with a flash light. This is an upgrade.
4. The only maintenance I would recommend is if the water separator get water in it from condensation or steam... just push the little release valve open and drain water. As for the cell, IF you take the top off replace the Teflon tape and rinse out. You can if you choose, wipe out the inside of the cell, but its not necessary.
5. It depends on what I have. I'm just one guy. Right now it is 7 days for me to get build materials. 2 days to assemble. and however long shipping takes. These are business days.
I would like to get group orders, but I understand the situations.
Thanks for your interest.