Delay between reals values and simulated values

Hi,

I am building an ASM2dISS simulation, one primary clarifier, 5 bioreactors and 1 secondary clarifier at the end.
The secondary clarifier considers SST.Takacs SVI and it seams that it has no delay. The surface is 67824 m, and H is 3 m.

But maybe is not from the secondary clarifier, but I have a delay of about 0,158 days between the reals values and the simulated values. (The simulated results come first )

Where do you think this delay is coming from?

Thanks.