Does anyone know of a water flow meter that works with the Cerbo GX? I'd like to have a meter on the water pump of my RV such that the total amount of water that has been pumped will display via the Cerbo. So if the RV water pump has pumped 10 gallons for example, one of the items on the Cerbo display will say exactly that. Does anyone know of a sensor like this that will work with the Cerbo GX units?