In simple terms.
1) Put a tee piece into the pipework after the pump.
2) One of the exit points goes off to pole as normal.
3) The other exit goes back to tank.....but somewhere along this line you need to put an adjustable tap in. It's this tap that adjust the flow rate at the pole by means of how much water you allow to go back to tank. The more flow back to tank the less flow at the pole.