The electrolytic coatings with high corrosion resistance, hardness and wear resistance are widely used in various industries. These requirements are most satisfied by electrolytic chromium coating. However, the compounds from which they are obtained contain hexavalent chromium, which is considered to be environmentally harmful substance. The alloys based on refractory metals (W, Mo) with iron-group metals (Co, Ni, Fe), electrolytically plated from citrate-borate and glukonateborate electrolytes, thanks to its functional properties, are the best replacement of electrolytic chromium coatings. Typically, these coatings are nanocrystalline, which leads to good functional properties. The possibility to obtain such coatings is largely determined by the composition of the electrolyte. This paper is devoted to investigation of the properties of such solutions after the long exploatation of the electrolyte. The long-term operation was carried out in electrolytes of the following composition (mol/l): №1. Na2WO4 • 2H2O - 0,2; CoSO4 • 7H2O - 0,2; C6H8O7 - 0,04; Na3C6H5O7 - 0,25; H3BO3 - 0,65, №2. Na2WO4 • 2H2O - 0,05; CoSO4 • 7H2O - 0,05; C6H11NaO7 - 0,55; NaCl - 0,51; H3BO3 - 0,65. The electrodeposition of coating on steel substrate was carried out from the electrolyte № 1 at current density 1 A/dm2, and from the electrolyte №2 –at 3 A/dm2 at 600C. The deposition was carried out in the presence and without stirring. The photocolorimetric determination of Co and W concentration in the solutions was performed. The reaction with nitroso-R salt was used for evaluation of Co2+ concentration. The W concentration was determined using the reaction of reduction with Sn (II) and Ti (III) to W (V) with coloured thiocyanate complex formation. It is shown that the electrolytes composition changed during exploitation. It is noteworthy that in the citrate-borate electrolyte at relatively low values of passed electricity detectable concentration of the studied ions increased. This phenomenon can be caused by the destruction of the citrate complexes of Co and W release of ions in the process of electrolysis. On the other hand Co2+ and WO4 2- concentrations decreased the electrolyte with higher values of passed electricity (Q, A•h/l). The Q values corresponding to observed decrease depended on the volumic current density. At smaller values of the volumic current density the determined concentration maximum was achieved at lower Q. This is most clearly evident for the WO4 2 concentration changes. Another remarkable feature of the citrate-borate electrolyte composition variation was the more sharp change of the WO4 2- concentration and less sharp change of the Co2+ concentration in the absence of stirring during the electrodeposition The determination of the coating composition from the citrate-borate electrolyte showed that in the absence of stirring W concentration in the coating is more than in the presence of stirring. That allows us to understand the cause of the sharp change of the WO4 2 concentration in the electrolyte during the deposition without stirring. The citrate-borate electrolyte composition changes were studied during exploitation period up to accumulation of the passed electricity 10 A•h/l, but the gluconate-borate electrolyte have studied up to about 2 A•h/l. In the process of electrolysis with stirring, the WO4 2-concentration decreased more rapidly than in the absence of stirring (in contrast to the electrolyte №1). The Co2+ content in gluconate-borate electrolyte decreased at a slower rate in the presence of stirring than without it. This also distinguishes the behaviour of the electrolyte N2 from the behaviour of the electrolyte N1. The study of the gluconate-borate electrolyte properties will be continued later.