Hi. Just a quick comment...

I want to predict the tank volume

I believe you will also need to factor in the time interval in order to
predict volume. When demand is greater than supply, the longer this
situation lasts, the lower the volume.

I am working with an extremely large spreadsheet

From a Solver view, keep in mind that Solver can have only 200 changing
cells. It sounds like it won't be an option here. Also, the tendency
here would be to use IF(), Max(), and Min() functions in your model.
Solver won't work well if you use these functions.


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Dana DeLouis

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