[en] Among the various iron-arsenide-based superconductors, members of the AFe_2As_2 (A = Ba, Sr, Ca), the so called 122 family, have become model systems for exploring superconductivity in this new class of high-T_C superconductors. Recently it turned out, that the different substitution series result in very different temperature-concentration phase diagrams, especially in the region where antiferromagnetism disappears and superconductivity emerge. Furthermore, the symmetry of the superconducting order parameter tends to vary from one substitution series to another. Here, we report on the optimization of the single crystal growth of SrFe_2(As_1_-_xP_x)_2 using the well-established self-flux technique. However, so far the exact melting temperatures of various flux to 122 compositions are not reported in the literature. We performed differential thermal analysis (DTA) to determine these melting points as function of flux to 122 ratio and for various phosphorous concentrations. Subsequently, the obtained samples were analyzed with electron microscope, energy dispersive x-ray analysis and powder diffractometry to determine the phase relations and distribution coefficients in this series.