The source used for the in-vitro tests was an upside-down wet-cup, shown schematically below. Compared with a conventional wet-cup, this design has improved flux stability because there is no air gap between the water surface and the membrane. It used a hydrophobic Sil-Tec membrane, which is impervious to condensed water but permeable to water vapour.

The protocol used was as described on the ISBS conference poster, ie perform 200 repeat measurements in rapid progression with each instrument. The VapoMeter measurements presented here are the same as the published ones, but the AquaFlux measurements have been repeated with a newer Model AF200 instrument. The raw data from which the histogram was constructed is shown below.