You may have a female or clamp end on both units, if so cut this off the switch socket and strip the wires so it inserts into the clamps on the osmolator pump wire, they do this because older osmolators lacked these squeeze clamps. You will just squeeze them insert the wires and release. The osmolator must have the pump speed turned up all the way to reliably switch the socket, you need to open the controller and turn the speed to max to do this, this applies to any osmolator made after nov 2011. After that, plug in the osmolator and the switched socket, the pump of your choice will plug into the switched socket and the osmolator will then switch it on and off as needed.
Yes, we know this is not well covered in the manual and a revision is planned soon.