Generalized approach to electrolytic systems (GATES) with generalized electron balance (GEB), denoted as GATES/GEB, is the best possible thermodynamic approach to electrolytic redox systems of any degree of complexity. A complex redox D+T system, with KIO₃ + HCl + H₂SeO₃ + HgCl₂ solution as titrand D and ascorbic acid C₆H₈O₆ solution as titrant T, is formulated and simulated according to GATES/GEB principles. In this metastable system, 51 different species are involved in 8 (charge and 7 elemental) balances, and interrelated in a set of 41 independent equilibrium constants. Five elements (I, C, Cl, Hg, Se) in this system were assumed a priori as electron-active elements (‘players’). Some thermodynamically possible reaction paths were thus released/allowed, and resulting effects are compared with the curves obtained experimentally. Other advantages of the GATES are also discussed.