Ratios of the EWs of the Ca II Triplet lines EW3 and EW1 with respect to the strongest line, EW2, as function of the S/N per pixel for individual VLT/FLAMES LR8 spectra that are likely members of the Sextans dSph with G < 19.7. Blue squares are spectra that do not meet the vdiff criterion. The vertical dotted red line in the upper panel is at S/N = 16 per pixel, which is the cut for accurate [Fe/H] measurements based on EW2/EW3. The horizontal dotted blue lines are limits of the values of the ratios at 0.9 < EW2/EW3 < 1.7. In the lower plot, red star symbols do not meet the limits in the upper plot for EW2/EW3. The dashed horizontal red lines in both panels show the mean of the ratios at a S/N > 40 per pixel.