Steve,

I use this adjustable pressure regulator.  I'd have  the hose barb style
but I'd go with the threaded one if I had to do it over.  Finding a 7 mm
hose barb tee was nearly a miracle for me.  The double diaphragm is mine
but I believe the single is more than adequate.  Made in Italy. I've had
a a year with no complaints.

Sincerely,

Mark Keller
91 Carat
Cowichan Bay BC