Influent (inflow) and sampling The influent (inlet or inflow) of simulated nursery runoff con-taining representative concentrations of fertilizers was preparedusing an automatic irrigation system MCU Ferti®(Multi Computer Unit; FEMCO, Damazan, France). The effluent (outlet or outflow)was the liquid that has suffered the treatment through the bed of the constructed wetland. The inflow and outflow pipes located in the wetlands were connected to the feeding lines of the two analyzers mentioned in Section 2.1.2.To check the performance of the system, samples from inlet an dout let were taken at the same time that display readings of the two devices were written down. Sampling was performed during two months (11/05/2015–16/07/2015).In order to check the response to changes of the measures made by the pieces of equipment, the set point of the electrical conductivity (EC) to manufacture the nutrient solution was down graded periodically. The change in the EC set point would change the nutrient concentration. This variability in the inflow concentration would provide variability in the readings of the instruments.