This invention relates to a hydraulic system comprising a hydraulic cross connection (90), housed in a housing case (99) to be mounted on a rear planar support (98), comprising inlet and outlet ducts (70, 71), at least one tubular element (105, 106) insertable in each one of said ducts (70, 71), and at least one quick coupling removable hook (91; 991), configured to be inserted in a seat (100) obtained on an outer wall of each one of said ducts (70, 71), the hydraulic system being characterized in that said at least one quick coupling removable hook (91; 991) is configured to be posteriorly inserted in the seat (100) and it comprises at least one rear arm (95; 995), and in that the housing case (99) is shaped so that a distance separating the seat (100) of each one of said ducts (70, 71) from the rear planar support (98) is such that said at least one removable hook (91; 991) is removable from the seat (100) and said at least one tubular element (105, 106) is extractable from the inlet or outlet duct (70, 71) to which the seat (100) belongs only when the housing case (99) is not mounted on the rear planar support (98). This invention further relates to the related kit of hydraulic accessories and to the related hydraulic system, as well as to a mixing apparatus comprising such hydraulic system.