[b]Good morning to all.[/b] I am very new to EPANET so I would like to share with you a problem in modelling a simple water supply network. My objective is to perform an extended period simulation. I have only an element reservoir and an element tank connected with a pipe. The element tank is modeled assigning all the parameters: diameter, initial level, minimum and maximum level. [b]Steady State Simulation[/b] I connect a junction downstream the element tank to which assign the mean demand (a constant value) of an urban centre in the day of maximum consumption. I connect the reservoir with the tank, run simulation and I get a constant flow in the pipe with the same value that is assigned to the junction. So the demand is satisfied. [b]Extend period simulation[/b] Now I assign to the junction a demand pattern to modify the constant flow assigned before (this represents the demand trend during a day). I assign all the parameters to perform a 24 hrs simulation. At this point the tank begins to fill / empty. It happens that the flow entering the tank stays no more constant, because it varies in time with the water level inside the tank, which depends on the exiting flow (the demand pattern). My problem is that I want to assign a constant flow (flow in the day of maximum consumption) as input to the tank, and that is not influenced by the application of a demand pattern downstream. I mean that I want to model the system fixing the delivery height of the tank's gateway, so that the HGL in the pipe remains the same as Steady State Simulation, is there a way to do this? Every kind of help is appreciated, thanks a lot.