a first pressure regulator in communication with said first reservoir for controlling pressure supplied through {TAIL ~ said pressure supply conduit} to said {HEAD ~ first reservoir}; and 
a first pressure regulator in communication with said first reservoir for controlling pressure supplied through { TAIL ~ said pressure supply conduit } to said { HEAD ~ first reservoir } ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH