A survey over the capabilities of a new simulation and data analysis program for laboratory, technical and natural aquatic systems is given. In this program, the spatial configuration of a model system is represented by compartments, which are connected by links. The program allows the user to define an arbitrary number of substances to be modelled and it is extremely flexible in the formulation of transformation processes. It not only offers the possibility of performing simulations of the time evolution of the user-specified system, but it provides also methods for system identification (sensitivity analysis and automatic parameter estimation) and it allows us to estimate the uncertainty of calculated results. These features, together with the user-friendly interface, very much support scientist in analyzing their data. Three examples illustrate the capabilities of the program.