ZnSxSe1-x (x = 0.08-0.12) substrates transparent for ZnSe QW emissions were used for the growth of ZnSe/ZnMgSSe structures. The FWHM of X-ray rocking curves of the substrates were 36-38 arcsec. Etching the substrate in diluted HCl to remove the oxide layer was performed as final treatment before the epitaxy. A variety of ZnSe/ZnMgSSe QW structures were grown by low-pressure MOVPE. All structures grown have strong ZnSe QW emissions in their PL spectra. For a MQW structure with intended well thicknesses of 4, 6 and 12 nm, well-resolved peaks of all QWs were observed.