After I get my system up and reliably running, I will change one of the ball valves (I have 2) under the hood with one of these.
Solenoid Operated Valve
I'll control it with a switch near the dash with electric only available when the van is running so that it won't suck juice when I'm parked.
Solenoid Operated Valve

I'll control it with a switch near the dash with electric only available when the van is running so that it won't suck juice when I'm parked.