A three-product dense medium cyclone produces clean coal, middlings, and reject from a single medium circuit by joining a cylindrical primary separator of the LARCODEM type to a conical dense medium cyclone fed by the primary underflow. Although the operator sets only one circulating medium density, a second and higher separation density forms on its own in the secondary cyclone, because the primary unit sends coarser magnetite to its underflow and finer magnetite to its overflow. This secondary density has long been treated as fixed and beyond the operator's control. This work tested whether it can be adjusted intentionally. A pilot gravity fed unit was run under eighteen conditions set by a Taguchi L18 orthogonal array in five variables: the primary feed pipe immersion depth, the primary vortex finder depth, the secondary vortex finder depth, the feed pressure and the medium density. Partition curves were measured with plastic density tracers of three sizes, and the cut point, the probable error, the medium stability, and the medium split were obtained for both stages. Second-order models linked the geometry and the operating conditions to the secondary responses. The secondary density shift and the secondary medium stability were described with coefficients of determination of about 0.63 to 0.91. The primary feed pipe immersion depth was the main control variable, with feed pressure and secondary vortex finder depth as additional levers.