I just started using Stan for wastewater simulations and see it very promising and relatively easy to use. I create first goods-level and input watervalues as tn/h with 10 % tresholds. I managed to get nice flow even with inner loops and added other layers like nitrogen and sulphur, but while adding phosphorus- level somehow my previous models went broken and even the water-level is not counting anymore to the end of the system. I have used both flow-values and relations and there should not be any contradictions in them. Some of the values are changing, even I would like to keep them constant... How to priorize what is given and what is counted?