We timed how much time it took for each air pump to empty a liter of water in the bottle. Due to the fact a liter of air displaces a liter of water, this gave us our stream fee in liters per moment (LPM), which we then converted to gallons https://ledfishtanklights27913.angelinsblog.com/21276280/5-simple-statements-about-automatic-fish-feeder-explained