Method and device for regulating the concentration of substances in electrolytes

The invention relates to a method and an apparatus for regulating the concentration of substances in electrolytes for the deposition of metal. The method is preferably used for the electroplating of printed circuit boards in immersion bath systems and in horizontal or vertical continuous systems, in each case using insoluble anodes. A method and an apparatus are described for regulating the concentration of metal ions in an electrolytic fluid, which is used for the deposition of metal with insoluble anodes and additionally contains compounds of an electrochemically reversible redox system. With the oxidized form of said system, metal is dissolved in an ion generator , traversed by the fluid, so that these compounds are thereby reduced. For the deposition of metal, the dissolved metal ions on the item to be treated are reduced. The compounds of the redox system in the reduced form are oxidized again on the insoluble anodes in the electroplating system . In order to keep the concentration of the metal ions in the electrolytic fluid constant, at least a portion of the electrolytic fluid, contained in the electroplating system, is conducted through one or a plurality of electrolytic auxiliary cells