Because in that thread I was using a Latching Relay which interfaces with ESP by two Grove 3-pin connectors (for switching to A or switching to B)
and a regular Solenoid Valve ... pretty easy to program in ESPHome ... and then another user asked
MUCH less power required to do the latching at the Solenoid ... and so off down that rabbit-hole ... but I only found some on aliexpress which have two wires and look like this
I started a new thread since this seems a very different piece of hardware and I didn't wish to confuse the two issues - especially since I may need to go back to the other thread if this Latching Solenoid Valve doesn't work out.
Back to the Latching Solenoid ...
I understand that a regular relay or solenoid needs power applied to turn ON and hold it ON, and opens the contact immediately the power is removed effectively turning it OFF. I guess this is what you mean by "When it is positive, it is on. When it is not positive, it is off".
However a latching relay stays in its current state when the power is off. I assume that "positive pulse open valve, negative pulse off" is requiring a +4.5V 30ms pulse to open the valve, and a -4.5V 30ms pulse to close the valve. In effect a +ve voltage is when the electrons flow in one direction, and -ve voltage is when they flow in the other direction
Continuing down the rabbit-hole I think "DPDT relay" and "H-Bridge" are the keywords I need.