Hi Pole king
Although one controller will run two pumps its not really designed to do this. You will find the system is not very efficient . you are likely to have issues with poor flow, controller cycling the pumps in out of DE unexpectedly. The main issue will be getting calibration on the controller right when it is trying to manage two pumps.
This is because there will be differing pressure in the two poles/hose lines and the pressure the pumps will work at. Plus the amount higher of current two pumps will draw.
Water will always look to take the easiest route so a pole working at a lower height will have better flow than than a pole working higher, you may find that to force water to the higher pole you will have to use pole taps to restrict flow to a lower pole. Restricting one pump is this way will increase the current draw off the pump as tries to push against the restriction.
Calibration will be difficult as you will need to have both pumps running in order to calibrate, There is also the likely hood that stopping flow to one pole will mean the control dead ends both pumps at the same time. With one pole flow stopped the controller may cycle in and out of DE on both pumps or stop both pumps.
The controller is max rated to 10 amps, With one controller running two pumps each pump is going to pull 3 to 5 amps from the battery putting you very close to the max limit for the controller. If the current limit is exceeded the control will shut down both pumps and display OC ( Over current)
Over current protection is just one of the safety features we place on the controllers to protect you the system and the controller
So in summary if you are going to try this the pumps will both need to be calibrated at the same time, To avoid the controller cycling in out of DE both line will need to be stopped at the same time. Also to ensure you do not exceed the max current rating of the controller and have both pumps shut down flow rate will need to be less than 40 - 50 to ensure the two pumps combined can not pull more than about 3 to 4 amps each.
Having one controller for each pump will be a far more efficient way to operate as it will give you two independent systems with each pump/controller calibrated and avoid the issues mentioned above. Having a more efficient system will quickly recoup the cost of a second control
Lastly with a two pump system a battery of 110AH would be best. The reason for this as mentioned above two pumps are going to pull 6 - 10 amps an hour out of a battery. Ideally you should not reduce battery capacity below 50% or 10.5V below this the battery cells will be damaged over the medium term. In effect with a 110AH battery you have 55 amps of usable capacity EG 6 amps divide by 55 giving approx 8 to 9 hours use before the battery will need charging