MBR tanks starts out at 1000 m3 at default

Hi. I am using the MBR tank model. The MBR tanks starts out at 1000 m3 at default no matter what I put in at V_Tank and V_Min.

I attach 3 screen shots that demonstrate some of my configuration.

Implemented a timer to empty the tank down to V_Min to for the first 2 days. But how can I make it start at the value I want?

You are right.
The initial volume is implicitly set by the [b]initial mass of water[/b] (the mass vector M is a derived state variable: you can set initial states in the Variables tab page of the Block Details).
Conversely, calculating the initial mass of water from the volume (which volume: min or max?) would also not be ideal - unless of course one would add a 3rd parameter, next to "V_Max" and "V_Min", e.g. "V_0". In which case, you could add the following [b]initial equation[/b]:
[code]state.M[IndexOfSolvent] = parameters.V_0 / parameters.WWTPSpecificVolume[IndexOfSolvent][/code]

Thank you. That helped :)