The "Assembling and sealing up the OpenRov" assembly instruction includes "Optional but Recommended Step 4: Vacuum test the E-tube"
There is a link to a recommended vacuum tester but no instructions on vacuum testing.
My guess is that the vacuum tester is attached to the one of the vent ports, the pressure is lowered in the e-tube, and then the stability of the pressure reading is observed. Is that about right?
Any recommendations on the vacuum to attain or observation time?