Hello,
I don't fully understand ...
Yes: the aerator model uses temperature as parameter (manipulated variable, in fact); and so is the activated sludge tank model.
You can provide the two values individually (e.g. by manually inputting the desired value); or, probably better option, by using a top-level interface variable, linked to both temperature values.
I don't believe either of these options would result in an error of that sort. If you get the same error, can you please contact mikebydhi@dhigroup.com with a screenshot and the logging?
Three different temperatures will result in different steady-states of your system: what do you mean by "calibratin the parameters"? which parameters are you referring to?