The melt quality of an Al casting alloy has been examined by employing different experiments: reduced pressure test, H2-meassurement, PoDFA, fatigue and tensile test. Special emphasis has been given to the influence of oxides. The aim of this work was to determine the existing melt quality and to evaluate various methods used with respect to improve the quality. Experiments were conducted to check first the measuring methods and test parameters. When the current melt quality was ascertained, tests for potential improvements were made that determine the influence of accumulated impurities and handling, and finally two alloys are compared. The influences on the melt quality have varying degrees of affect on the tests used. It was seen that it was necessary to differ between new and old oxides in the melt, because of their differing influence: new oxides impact on the pores while old oxides impact on the inclusions. The pores in the metal are responsible for: the failure of the material in the fatigue testing, the amount of pores in the ground surface of the reduced-pressure-test sample and the density-index. The inclusions in the metal are responsible for: the failure of the material in the tensile test and the sum impurities of the PoDFA. Based on the results of the measurements suggestions for improvement for the melt quality were developed.