I am modeling a city water system using H2ONET v10 and I need to have a pump that runs at a specified flow (it is currently netting me a -457 ft of pressure head and all of my nodes are around -10k psi). I am using a pump curve for a booster pump that runs in a very narrow range (12-18 GPM) with a net pressure head between 100 and 200 psi. What can I do to model this type of pump?