What kind of radio are you using? Does it have atleast two mixes within its tx programming?
The "Master" is the valve & the "Slave" is the pump. And you need to have the pump on an esc too. Might work with a relay switch too, but the esc will have softer start/stops of the pump & you don't always need full power for every movement -> which will help conserve run time too.
I've done this with my adt & 850 hoe, works really well! I have a yt vid of the adt that shows how well it works.
Much less expense, as well as much less junk inside the model too.