The residual distribution method is used to solve the multi-ion transport and reaction model in turbulent flow. The model describes the effects of convection, diffusion, migration, chemical reactions and electrode reactions on the concentration, potential and current density distributions in an electrochemical reactor. The Reynolds averaged Navier-Stokes (RANS) equations are used to calculate the turbulent flow, with the turbulent viscosity obtained from a low-Reynolds number k-omega model. Different turbulence models for the turbulent mass transfer are examined and validated in a parallel plate reactor for the deposition of Cu from an acid copper-plating bath. The most accurate turbulent mass transfer models are the algebraic model for the turbulent diffusion and the newly suggested model with the constant turbulent Schmidt number equal to 4.5. Furthermore, it is shown that the turbulence model for the mass transfer influences the local concentration distribution considerably but has much less effect on the current density distribution. (C) 2003 Elsevier B.V. All rights reserved.