You could always collect rain water, it’s pretty free of minerals, and filtered through a filter paper it’s good enough for topping up lead-acid batteries.
14 Likes
-You MIGHT be able to use a pressure sensor, Then you can figure out the airflow by the pressure. 
-
hydrogen peroxide will kill the bacteria.
-
Diaphragm pumps are okay to run dry. But if you want to do actually water metering, they have other pumps, that essentially all they are is a wheel controlled by a stepper motor with rollers on it that roll over a tube to squirt precise amounts of water.
5 Likes
“peristaltic pump” is the search term for the metering pumps. Lots to choose from on Amazon.
9 Likes
I watch your videos that some how I missed. Very nice work on your build and improvements you have made. Thank you for the drive with you in your car and the beautiful country side.
8 Likes
Bob,
Thanks for riding along and for the nice comments.
10 Likes