vial                            date           treatment               time_elapsed  Fe_II_concentration  standard_deviation  
PV-1_ASWkan_ferrozine_vial_2    2016/11/05     ASW 2                   72            0.002437676          0.000997925         
PV-1_ASWkan_ferrozine_vial_2    2016/11/06     ASW + kan 2             96            below detection      nd                  
PV-1_ASWkan_ferrozine_vial_2    2016/11/07     ASW + kan 2             120.5         below detection      nd                  
PV-1_ASWkan_ferrozine_vial_2    2016/11/08     ASW + kan 2             145.5         below detection      nd