Sounds to me like you got your wires crossed when you replaced the solenoid. Recheck your connections at the replaced solenoid.

"When i turn one zone on, ALL zones get power at the controller, but NOTHING actually turns on."

What exactly do you mean? When you activate 1 zone from the controller you are getting a volt reading on all the station terminals?

Do you have a weather sensor?
Do you think there could be any wires broken or damaged?
Did you take a volt reading at the solenoids?
When you switch the solenoid out did you cut and splice into old wires from previous solenoid or did you go back to orginal wire connections and redo?
If so I would redo and check the wire connections.

Hi ela,

I concur and double concur with ri. Take reading at the solenoid wire connection when the station is on. Recheck all the wires for continuity from the controller to the valve. Aloha.