On Sat, 30 Dec 2017 09:48:17 -0800 (PST), Sonny
wrote:

On Saturday, December 30, 2017 at 11:22:29 AM UTC-6, wrote:

Gotta make sure to get all the air out of the tube, though.

And your tube needs to be 3/8" dia. or larger, I was told. A smaller dia. tube would allow for the water's adhesive forces to affect the internal flow, possibly giving an inaccurate reading..... and probably more so with a longer tube.

Sonny
strictly theoreretically, the small tube should eventially be just as
accurate as the larger one but it might take half an hour to rersolve
instead of half a second - - -