In my Kangaroo ( my first jet and instal ) I have my shut off valve between the UAT and the pump, I haven't got a leak in this instal been two years old by now, I have learned here on RCU the the Festo fittins and valves where designed to be use under pressure not succion, it worry me in the begining but I never got a leak on the Roo instal, never change it but now days as you can see I prefer to intal my Festo valves on the pressure side and yes I have used the other valve, the one with barbs lots of times.