To improve the mechanical properties, the castability as well as the corrosion resistance of magnesium alloys, aluminium is frequently employed. As a rule, technically relevant alloys contain between 3 and 9 wt% aluminium. Normally, aluminium contents under 3 wt% is said to have no corrosion reducing effect. In order to investigate the influence of specific additions of aluminium, various methods are employed in practice and different electrolytes or concentrations of saline solutions are used as testing media. In doing this, it is rarely possible to compare the results. For this reason, the current work both discusses the influence of aluminium and the effect of different saline solutions on the corrosion behaviour of low alloy magnesium–aluminium alloys as well as compares two different measuring procedures (electrochemical and gravimetric).