Sorry Andy - my table of results didn't send as it was typed but basically the upper cylinder continued to show 4.25 PSI in it while pressurizing the Lower cylinder - even after 24 hours and a drop from 7 PSI to 3.5 PSI
The upper cylinder showed 0 PSI in the lower cylinder over a 16 hour period and a drop to 4.75 PSI from the original 7 PSI