The invention relates to a novel phosphate mixture, which is characterised by the excellent solubility thereof in water and in aqueous solutions containing salt (brine). The novel phosphate mixture is characterised in that it is made of the following components: 1) 60-85 wt. % of a clear-soluble potassium tripolyphosphate having a P.sub.2O.sub.5 content of 46.0 wt. %-47.0 wt. %, preferably 46.4 46.8 wt. %, especially 46.4 wt % and a K.sub.2O/P.sub.2O.sub.5 Mol ratio of 1.70 1.78, preferably 1.73 1.75 and especially 1.74, 2) 15-39 wt. % of sodium polyphosphate NPP, 3.) 1-5 wt. % XH.sub.2PO.sub.4, whereby X.dbd.Na and is K, whereby the mixture has a pH-value of between 8-10, preferably 8.5 9.5 and has an opacity in water and brine of <5 TE/F.