We present internetwork quiet Sun spectropolarimetric observations taken simultaneously at the Fe I lines at 630 and 525 nm. The magnetometry at 630 nm in these low flux regions of the Sun's photosphere has been put in doubt by a recent work. The 525 nm lines are supposed to give reliable results concerning the magnetic field strength in regions where the magnetic structures are not resolved. We study the compatibility of the results obtained in both spectral ranges to confirm or deny the affirmation that the 630 nm lines are not valid for recovering the magnetic field strength at the internetwork quiet Sun. We conclude that both the 630 nm and the 525 nm pair of lines give no trustable results concerning the magnetic field strength. However, the magnetic flux density is correctly recovered from both spectral ranges.