Well then set it up to run both then, and have valves on em to throttle them back if needed .... Easier to turn both down a tad rather then one down a lot right ? .... And ya can always open em up if ya think it to slow.... But I would look up your pump online to find out how many gph it does when it a certain amount away from the tank or your case tanks.... That gonna play a BIG amount if the real amount of gph ya will be moving once ya know how far the pump will be from were it returns into the tanks.... Running mutiple tanks ya may only be running at 2500gph at full throttle once it all hooked up , all depends how far away the pump is from the return in the tank