If the mist system was installed at Milltronics, the solenoid valve is inside the mist unit and you wouldn't get enough air flow to be effective. You can break into the wiring for the mist unit and use it for a different solenoid.
I have installed quite a few of these:
Valve, Solenoid, 1/8 In - Solenoid Air Control Valves - Valves - 6JJ53 : Grainger Industrial Supply
You will need a needle valve like this:
Needle Valve, 1/4 In NPT, 600 psi, Brass - Pneumatic Flow Control And Needle Valves - Valves - 5TUL2 : Grainger Industrial Supply
(or something like them)
Plumb this with a few fittings and some nylon tubing and it works great.
(I have no connection with Graingers other than as a satisfied customer)